It solely depends on ones intend, it does has nothing to do with different times of the day! There are several ways of doing it, one can for once, like you already mentioned, do this using Photoshop, or one can do this in-camera, without the use of a computer.
There are many different kinds of this as well, bracketed shots for HDR, multiple shots for composits, strobe shots (Multiple flash exposures for displaying several stages of motion in a single image), this can also be done in pp without the use of flash, combining multiple shots for focus stacking, etc., there are just many kinds of doing this, as well as many ways of doing it!

No creative art can thrive in a vacuum. There has to be:
* demand for its works
* funding (patrons)
* legal protection for creators/performers/artists
* education (a young dancer doesn't get to be a prima ballerna by buying a copy of Ballet for Dummies
* facilities, materials and tools
* a "scene" -- people who know about and appreciate the art form

It's rather like sports: it takes 12 million American kids playing basketball to create 300 NBA players.
And that's assuming there are enough coaches, scouts and college teams to develop these players.
Kids don't have to pay for the coaching they receive in school or in college--or to rent the court.

By the college level, coaching is pretty good. But who trains photographers? Get your Four Thirds
camera and your copy of PhotoShop and you're on your way to being Ansel Adams....uh, not quite.

Wedding photography can exist as business as long as their are brides who want photos of their wedding,
but fine art photography requires galleries, collectors, and museums. Portrait photography requires
sitters willing to pay for portraits.

Dorothea Lange didn't pay out of her own pocket to photograph migrant workers--the FSA paid.
Ansel Adams didn't pay out of his own pocket to phtograph the National Parks--the Park Service paid.
Alfred Stieglitz's phorotraphic work was supported by his gallery, An American Place, in NYC.

Money has dried up, many galleries have closed, sitters have become scarce.

Ask yourself: what is the most I ever paid for a photographic print? Now consider: Andreas Gursky's original
photograph "Rhein II " (1999 -- a chromogenic color print, measuring 73" x 102", mounted on clear acrylic).
It sold at auction at Christie's in NYC in 2011 for $4,338,500 -- the most ever paid for a photograph.
What would it have fetched at your local photo gallery (if there is one)?

Finally, technology is not neutral: some technologies provide a unique, permanent original , others
do not. You're lucky to get more than $400 for an ink-jet print, unless it has already been sold several times
and has unimpeachable provinance.

Manufactuers just want to sell gear. They don't care whether or not its capable of producing valuable prints.
Most buyers don't care either: they think with a Four Thirds camera, a copy of PhotoShop, and one of
Bryan Peterson's books they are all set to be the next Ansel Adams. They don't realize that they would have
a better chance with a camera made from a shoe box.

Automation prevents new photographers from learning the very things that are most important to photograph.
Subminaiture format (almost the same size as 110 cartridge film!) limits quality print size (for straight photography).

If you want to paint a ceiling like Michaelangelo did in the Sistine Chapel, you better not be using a roller
on a pole. Sure that's "higher tech" than a brush, and it's more efficient and conveneint (no lying on your back
on a scaffold for hours and hours). But it just won't look the same.

Each person chooses his priorities as a photographer: is your top priority print quality and value, or camera convenience
and compactness? Do you want "bells & whistles" or image quality? Joe Consumer has made his choice: tiny,
"high-tech", convenient and cheap!

According to Bureau of Labor Statitics estimates, there are only 49,320 people employed as professional
photographers in the US as of 2017 -- out of a population of 326 million. https://www.bls.gov/oes/current/oes274021.htm

Even if every pro in America bought a new camera every year, it would have nelgibible impact on the sales the big
Japanese camera makers. From a marketing standpoint, pros don't matter (except as paid endorsers),

The future of photography is in the hands of consumers--and since 2011 they have been deserting in droves for
smart phone cameras. The market trends say that the future of photogrphy is smart phones -- which means it has no
future except as a consumer passtime: creating images so that they can be deleted within a short time.

No other artist has to compete with consumers for the attention of suppliers. Nike does not make ballet slippers.
Crayola does not make artists' crayons. Sherwin Williams does not make artists oil paints. First Act does not make
violins for concertmasters.

What camera manufactuers do not sell primarily to consumers? Off hand, I can only think of Hasselblad, Sinar
and Phase One/Leaf. Yashica is gone, Zeiss hasn't made a Zeiss Ikon camera since 2004 (and the Zeiss brand for
lenses is licensed to Sony), Voitlander is a zombie brand, and the Mamiya brand is controlled in the USA by a
different company than the camera manufacturer,

Photography only became accepted as fine art around 1900-1930 thanks to the efforts of Alfred Steiglitz
and a three generations of brilliant photographers. Pictorialism began the process of getting photography
taken seriously, but it could not have survived modernism. The "straight photography" got photography
accepted as modern art. But there is no guarantee it will retain that status.

Older works will continue to appreciate and new works by established photographers will command high
prices, but it has gotten very difficult for younger photographers to break into the fine art market, and soon
it may be nearly impossible.

If you want to feel young, check out the ages of the living photographers whose work commands the top prices.
None of them is under the age of 50. Thomas Demand is 55. Andreas Gursky is 64. Sally Mann is (a lovely) 67.
Annie Liebovitz is (a very young) 69. Bruce Barnbaum is 76. Don McCullin is 84.

Photography (the art form) is probably entering a "dark age". But fauxtography (what people do with smart phones
and "selfie sticks") is bigger than ever!

How much are you willing to pay for a stranger's "selfie"?

So how would you explain the more than 70% decline in global shipments of
digital still cameras between 2011 and 2017?

During this period, sales of smart phones grew substantially.
The trade press thinks the two facts are related, and I'm inclined to agree.

Camera manufactutres provide an upgrade path: from compact P&S to "bridge camera"
to high-end. But there is no upgrade path from an Apple iPhone to a digital camera.
Apple doesn't make cameras. And which digital camera will make phone calls?

Finally, there has been a change in the marketing of cameras from a focus on them as
cameras to a focus on them as "technology". From everything I've read about him,
Edward Weston didn't care a whit if his view camera had the very latest anything.
But digital cameras are now market more like personal computers.

The art world is very different: everybody understands that innovation in art isn't
about using the very latest paintbrush. And musicians are willing to pay a lot for
a 1956 or 1963 Stratocaster. And it's not just rarity: reissues of classic eletric guitars
are very popular.

Fender also makes Strats with active pickups--the latest electronics, offering reduced
hum, a better tone control and a volume control that doesn't change output impedence.
But most players prefer passive electronics--so Fender makes both.

I don't understand why photographers have bought into the techmology treadmill,
and are willing to accept a technology that is less capable (e.g., lower resolution)
just because it is more convenient.

If musicians cared only about convenience, then Casio would have put Steinway out of
business years ago, and Fender would now mostly be selling elecrtic ukeleles.
Fortunately, musicians care about how the music sounds. An instrument with a lot of
electronics is just as likely to sound bad as an acoustic instrument--perhaps more likely.

I suppose it's because people expect art and music to be difficult, but camera manufactuers
(beginning with Eastman Kodak) told the public that photography was easy and convenient.
(To it's credit, Kodak's photography books were much more realistic than its advertising slogans.)

"You press the button; we do the rest" -- when are people going to stop beleiving that?

The smart phone camera is just the next level. "You don't even need a camera to take pictures--
just use your phone!"

Someday people are going start looking at photographs again, and they are going to wake
up suddenly with a bad hangover. It was a great party, Apple and Samsung made a lot of money,
but now look at all the trash that's left behind! We've gone for 30 years with very few good prints,
and very few images that are going to survive.

Most of the digital images that have ever been taken have already been deleted or lost. But photographs
were stuck into albums and cherished for generations.

To steal a phrase from Marshall McLuhan: In the future, photographs will last for 15 minutes.