Does “in the watch world” only apply to fancy watches? I have a $200-ish Seiko Kinetic and have never worried about rain, washing my hands, or even taking it in a pool. I don’t even remember what the rating is — I just know I looked at it once and decided not to worry about it because I never go below a few feet underwater.

probably fine with a seiko but from what I recall you generally want to see 100m to never worry about it. I think 50m is general water resistance and 100m is maybe you can swim with it. probably better to confirm with your own research if you get a fancier watch in the future.

It seems pretty counterintuitive that "50m water resistance" wouldn't satisfy swimming in a pool.

on a Seiko its usually pretty good but again its kinda in the "it depends" category.