After the 2nd screen repair the phone has never worked properly, and the face ID stuff stopped working. All in all repairers couldn't do anything about it. That's why I think it's worth putting a cover on it.
I also hide my ID in mine (between cover and phone) so that I do not have to wear a wallet...
And my kids occasionally handle my phone, I don't want to hold my breath every time I see them walking with my phone in hand.