A couple of things-
We all have to start somewhere.
Many people will click away with their phone for years and never get anything more than snapshots. My wife probably hasn't touched a "real" camera in years but I'd also guess that she may have taken more photos in the last month than I have.
With that said, she would never say that photography is a hobby of hers. She has, to my eye, taken some impressive photos but they're mostly just documenting her life.
At the same time, there are a couple of old sayings like that everyone has to start somewhere, and the best camera is the one you have with you. Most people have a smartphone now, whether or not they even realize it has a camera. For some people, it's just a convenient way to share a recipe(been watching my wife have photos of those fly around with her family the last couple of days) or to remember where you were.
For others, though, maybe they find they enjoy taking pictures and start paying attention to what looks good and what doesn't. Maybe their "vision" evolves from there and they eventually realize that a phone may not do everything they desire and move on to a more advanced camera, or maybe they continue creating great art with their phone.
They you have the other example of accomplished photographers who might make a creative decision to undertake a project with just their phone or other limited equipment compared to what they "normally" use, or just to take a photo because something catches their eye and that's all they have with them. I have a good friend who's quite an accomplished pro(doing things like taking a lot of official studio photos for the Indy 500 and other events around Indianapolis) and seems to go in a cycle of deciding he's going to retire then getting sucked back into another project that interests him. I've seen some amazing iPhone work from him-both seen him taking it and also seen the results. I've seen him post a "just a crummy iPhone photo" that is better than what 99% of people can do with a full featured camera(although his "real" work is mostly now with a D850 or Z7). If Galen Rowell were still alive, I'd be shocked if a significant body of his work wasn't taken with a smart phone.
To the quality of results, though-some people are gearheads(I can sometimes fall that way) but I still enjoy getting results with them. Sometimes my work is crummy, and sometimes I get something halfway decent. Am I allowed to call myself a photographer because I don't always turn out good stuff? I'll leave that up to you all to figure out.
On hobbies more in general-I have been a collector all my life. I collect cameras, watches, fountain pens, and plenty of other things. To be a serious collector(not accumulator) there is a level of dedication involved. My watch collection is where I have probably dug the deepest. I've spent 10 years now compiling data to hopefully write an article on one specific watch I happen to really enjoy collecting(to the point of now over 50 examples) but every time I think I'm ready to put it together I find something new that just shakes everything up. To further my research, not only do I talk to others but I travel to shows/conventions(or did before COVID). I do things my wife thinks are crazy like call museum curators and make appointments to look at/handle items in their collections, and at the same time when I still lived in Kentucky I more than once gave opinions and/or appraisals for museums on donated or found pieces in their collection. I'm actually crawling out of my skin right now because I had a random email show up in my inbox a few weeks ago from someone who has a watch that made in the 1850s in my home town and wants to show it to me-I got photos and my outloud reaction was a couple of words I don't normally say. I called someone else who had looked at it and that guy told me he'd had the same reaction on seeing photos. That's a serious digression, though, I realize, but it's something that I think I can call a hobby.