It seems like a lot of these phones have physical keyboards or are just more compact than the average phone too though - I see how that could be appealing.
I've been experimenting with flip phones for a while now, and my current daily carry (for when I carry it - I often leave it behind or power it off) is a Sonim XP3+ [0]. Battery life is "a week if I leave it on, two if I turn it off at night," and it's waterproof, drop proof, and a bunch of other mil-spec toughness proofs (I don't care about rapid decompression, ideally, but it's been tested for that).
And I can use it in gloves, in the snow, without trouble. The environmental range is quite a bit wider than most smartphones, and everything is an actual physical button, no virtual buttons or touch sensors.
[0]: https://www.sevarg.net/2023/12/30/more-flip-phone-sonim-xp3-...
You're right someone could uninstall all of the apps they don't want, but the apps (and the internet) are *addicting*. It's understandable that someone would want a phone where installing Facebook, or whatever, is impossible. If you buy a phone that is incapable of doing something, then it requires no will power on behalf of the user.
Even though I agree this solution is extremely hacky, it does work.
His secondary reason is he misses the early 2000s aesthetics, which is something I am more in tune with.
The same sort of practice as buying a box of "snack sized" potato chips because you have a habit of eating more than a serving at a time when you purchase a normal bag.
Size matters too. I have the three phones (all Android) on me and thanks what I'm not a 1.5m asian lady.