I did break a phone scene once by dropping it. But, running the numbers replacing it was actually cheaper than buying a new case for every phone, so IMO they are simply not worth it.

A simple plastic screen protector might be, but those always get bubbles.

Tempered glass screen protectors have been out for years now. Applied correctly, they don't have bubbles, and they really do help with impact damage. They also help with keeping the screen protected against key/other sharp object scratches.