I wouldn't. My iPhone has been caseless for ~3 years. Dings, falls, 3 drownings, small kids just brushing it against pavement, etc. It's feels indestructible other than few scratches that you need to look for. Battery can be replaced by specialist in 30 minutes or so.
Wasn't it waterproof it already would've wasted 3 batteries + 3 devices.
(Obviously not but OP's argument is moot anyways as waterproofing and a replaceable battery are not mutually exclusive, we already had phones and other devices with both)
Wasn't it waterproof it already would've wasted 3 batteries + 3 devices.