Lightroom is a very sophisticated editing tool. Most photographers with both Lightroom and Photoshop do over 90% of their editing in Lightroom alone and rarely if ever use Photoshop.

Lightroom is much easier to learn and use than Photoshop. Exceptional Lightroom features include synching edits to many images at once, easy to save and apply presets, and the catalog library functions including keywording and filtering (some of which you might be able to do in the Photoshop associated Bridge program).

But, as noted, Photoshop has many more features: IMHO illogically arranged and inconsistently applied. The biggest advantage I see is the ability to use layers which opens a new world of editing.

I would have to disagree on this statement. I rarely use PS, but do almost everything in LR. PS allows you to do things like clone out objects (which LR can do, but is limited), replace backgrounds, and much more advanced things like compositing, adding text, etc. However, in LR, you can do all the things you really need to do - adjust the exposure, black and white point, highlights, burn in or dodge elements of the photo that need it, sharpen, dehaze, and more.
PS of course can do all of those, too, but it is much more complicated, and you have to "open" each photo individually, which takes time. If it is a raw photo, you first go to ACR and guess what - you are using the same adjustments as in LR! And then, after all of that, you need to save it (a .psd file or .tif or whatever. Then if you need a jpeg for upload or whatever, you need to export it, too. Yes, you need to export in LR if you want a jpeg, but it is CTRL-SHIFT-E and Enter. Done. Very quick.
Sorry for the rant, but LR is often short changed and is actually very powerful.

Photoshop includes a built-in plugin called ACR or Adobe Camera Raw. This is basically the same EXIF nondestructive editor that Lightroom is. Every single slider that you can adjust in ACR, is exactly the same as if you had moved the same slider in LR. They are exactly the same. The difference is how the interface looks. Which doesn't mean a hell of a lot especially to those old time Photoshop users that started using ACR a long time ago. Many of those users don't migrate over to LR. But LR does have some OTHER features that are not included in the Photoshop application. Those are mostly features that have to do with organizing your picture files. But Photoshop also includes another built-in app that's called Bridge. This is Photoshop's organizer for your photos. Old time Photoshop users that have been using Bridge for a long time also sometimes choose not to migrate over to LR. Most newer Photoshop users start with both LR and Photoshop and don't venture into Bridge or ACR. They find that LR is simpler and sometimes they don't even open the photo into Photoshop.

The biggest difference between LR and PS is that PS is a Pixel editing software that does change the physical properties of the file that can and will make the pixels change therefore creating a completely different and new file from the original file. That doesn't mean that you will destroy the original file, but that you can and will if you don't know what you are doing. Yes, PS is way more complicated than LR.