Required for who? It's fine that you need it. But I think you overestimate the number of people who simultaneously go to pool parties, jump in with their jacket on, and don't have accidental damage insurance.
it’s nice that you don’t need it, but lots of people do. It’s a pretty basic durability/longevity thing.
don’t worry you can always move the goalposts back to “but you can waterproof a phone with a removable battery”, that’s a much more defensible bailey. “Literally nobody uses waterproofing” just was never a strong argument.
Older phones were already water resistant. You just couldn't chuck them in a pond.
It's a total non issue. If our Game Boys collectively survived our childhoods then a phone with far fewer ingress points is going to be fine.
You can't even use it in the rain because capacative touchscreens.
Waterproof phones are marketing.