I even put a case on a rugged phone. It does look a bit ridiculous.
I have one older phone that feels really nice without case, but I too put it in one, a wallet case, because it’s a secondary device, and thus is often in worse places. Possibly even a pocket with keys.

I’ve used phones without cases before, and never broke one. However, I did get to find out that one of them, new enough to have USB-C, had plastic camera lenses. Archos 55DC, to shame it.