Same to you my friend. Same thing for your post. At least mine was factual, yours was truly SNARKY.
There are a LOT of people out there who like gadgets, including me.
Over time, I have bought my share, and like many gadgets I have owned, most are no longer in use. Some folks who have bought this gadget, no longer use it because it really gets in the way more than it is helpful. Some folks have employed it and continue to use it. I have never had the need for such a gadget.
And further, neither do all of the 50 + folks I shoot with in Florida's wetlands.
In fact, over the past 5 years shooting around over thousands of photographers, I have only seen one, and at the time that young lady was not using it to photograph the fast flying Anhinga's that were zooming past us.

Yes, I am using a picatinny rail. Drill and tap a 1/4-20 thread through the rail and fix a simple cold shoe so it can be attached to the camera's hotshoe. These cold shoes have a 1/4-20 bolt attached and come with two knurled nuts. Use red loc-tite to fix the bolt to the rail so it will never move.

I do not use the dot sight for near objects so any slight parallex misalignment does not matter. The dot sight is on the camera is not intended for precision aiming but only for more easily finding BIF. Some talk about focusing on the eye of a BIF but I don't think many are capable of doing that. See my previous response regarding focusing.

My nickel's worth.

I have used the Olympus EE-1 Dot Sight for two years and it has definite applications for BIF (which is my preferred subject matter).

Here is how I use the device. I calibrate the sight for the anticipated acquisition range for my subject. Using BBF, I usually pre-focus at that approximate distance which assists the camera autofocus system by eliminating significant focal adjustments. When my subject appears at acquisition range, I point the dot at the bird, mash BBF and start shooting. Note that there is no attempt made to verify focus lock through the lens. This is a "trust me" technique. On my Nikon D850, I also am using the 3D tracking mode which allows the tracking point to move across the entire frame.

What you gain using this method is to reduce subject acquisition lag time, i.e., the time it takes you to locate the bird looking through the lens, then focus, then shoot. Looking exclusively at the dot sight, I reckon you can increase your acquisition time by at least 1-2 seconds which can be critical for BIF. Additionally, looking exclusively at the dot sight allows for easier tracking of the moving subject.

Please note: The best autofocus situation for BIF are those wherein the bird is crossing left to right or vice versa at a relatively constant focal distance. Birds coming directly towards you are the hardest for you autofocus to overcome. Additionally, this technique is most effective when there is no competing background which can drag off the autofocus. A clear sky background is best.

Contrary to some comments, the sight does require calibration because the sight mounted on the hot shoe is a few inches higher than the lens, which creates a parallax problem. Think of railroad tracks. They are parallel but at distance (infinity) they seem to merge together. The problem is, our subject must be captured much closer than infinity. Therefore we must adjust the dot sight such that the line it is pointed along intersects the line where the centerline of the lens is pointed. The line where your lens is looking cannot be adjusted. But the line where the dot is pointed can be adjusted so these two lines intersect at some distance in front of the lens, i.e., your anticipated subject acquisition distance. Of course the dot sight can be adjusted left/right as well as vertically. Calibration is a simple process and can be done somewhat accurately without a tripod. Simply point the dot at a specific spot at anticipated subject distance and hit BBF without looking through the lens. Then look through the lens and see if your aim point is in focus. If not, you need to adjust (calibrate) where the dot is pointed.

Here is an example one application for using the sight. Suppose I desire to capture hummingbirds at a feeder 15 feet away but I don't desire to have the feeder in my picture. By observation, I know the hummers frequently hover at a position very near the feeder, then land on the feeder and drink, then fly to the hover position again and again. I have a 400mm lens and my camera is set with a high manual shutter speed to stop wing motion (1/5000th). I have manually selected f/7.1 to create background blur for my crop, therefore I have a very shallow DOF. ISO is set to Auto. I could pre-focus at the anticipated hover spot and simply shoot when the bird goes there (without any re-focus attempt) but any actual bird hover variance in focal distance will result in an out of focus shot. Or, I could use the dot sight and when the bird hovers, put the dot on the bird, hit BBF and simultaneously start shooting. I can calibrate the dot sight on the feeder, which is at approximate acquisition range.

I apologize for this lengthy answer, but the dot sight does have limited application. My wildlife photo partner came up with a different solution. He mounted a red holographic hunting dot sight directly to his lens. This turned out to be cheaper than my Olympus product plus, by mounting directly to the lens, he almost eliminated the parallax problem and subsequent calibration issue.

Bubba

I use a red dot for Spring training to help smooth panning and tracking. It is easier and develops good technique. I do not use it in the filed because it IS DISTANCE DEPENDENT. If I dial in and adjust the sight for 50 yards and then a Heron at 15 yards the dot will not be aligned with the camera focal point.
I have been meaning to test it to see what the variance is for every ten yards to see if it is material.
Here is something explaining the angle issue and I see someone else responded they use CONSTANT method. I can't imagine always aligning the dot 3 inches OVER the focal spot but like anything I guess it could be learned. Photography is easier as you can discard wind and gravity issues.
Unfortunately the accompanying images did not copy. The Zero is an angle that meets at the target. Constant offset is like a set of train tracks that never meet.
------PASTE STARTS HERE --------
What is “Zero?”

Generally, shooters will zero their weapon sights – whether it is a laser, an optical sight or something else – for a certain distance. What does this mean? Picture the trajectory of the projectile as it leaves the muzzle of a firearm. Disregarding bullet drop, wind, atmospheric conditions and things of that nature, the trajectory should be roughly along a line parallel to the center axis of the barrel. Ideally, to target where the projectile will impact, the shooter would want to sight along that trajectory.

The line of sight for a scope or iron sights is a straight line between the shooter’s eye and one or more points in the sight. That straight line is a bit easier to visualize for a laser sight. Since sights are typically placed above, below or to the side of a firearm’s barrel rather than looking down it, something called parallax is introduced. Due to this offset, the line of sight and the center axis of the barrel are almost – but not quite – parallel. At some point downrange, where the two lines intersect, is where the sights are zeroed.

Pistol Zero

The image above shows this concept. Zeroing a sight for a certain distance is easy enough to understand and accomplish but, as you can see, at ranges other than the distance for which the sight is zeroed, the point of impact (POI) will vary from the point of aim (POA). In this example at closer ranges the round would impact above the laser dot while rounds fired at longer distances would impact below the laser dot. The further the target is away from the zero distance, the further the POA will be from the POI. Greater distance between the center axis of the barrel and the sight will increase the severity of the POA vs POI difference because the angle between the two lines will be greater.

An Alternative – Constant Offset

There is an alternative configuration for laser sights that is popular with some shooters that eliminates the problem of the sights only being accurate at one distance. The downside is that they are not entirely accurate at any distance. The upside, however, is that the inaccuracy is the same at all distances (again, disregarding wind, bullet drop, etc.).

Pistol Parallel

The image above shows the constant offset scheme in which the line of sight is parallel to the barrel’s center axis. You can see that the line of sight never intersects the line of the bullet trajectory, so the projectile will never impact where the laser dot is. However, since the lines are parallel, regardless of the distance the point of impact will be the same distance, h, above the laser dot. Of course, in the real world, there is bullet drop so gravity will eventually pull the projectile down across the laser beam. According to this ballistic chart, assuming a 2″ distance between the barrel axis and the laser aperture, that will happen somewhere after 50 yards (150 feet) – much, much farther than the average defensive firearm situation which happens between 0 and 21 feet. At these distances, bullet drop is less than bullet diameter.