Well, that's basically the issue right here. ;)

I read once that the average cell phone, at least after the mid-2010s, was so much larger than the early generations that it no longer fit comfortably or securely in women's hands. Men's, yes. Women's, no. I am one of those women whose iPhone 4 fit my hand just fine, but whose iPhone XS is always at risk of slipping out of my hand... unless I keep it in a case. Because a silicone case with a "gummy" texture gives it more grip.

So for me — and probably for a lot of women (who often get overlooked in "standard" design) — having a cell phone case is an insurance policy against drops and damage.... and the huge expense of replacing a phone. It does add bulk, but it enhances grip. For a phone that already feels too bulky in our hands, added bulk — in exchange for added security — is a worthwhile tradeoff.

Are phone cases an unsustainable and "necessary evil"? Perhaps. ;) But the emphasis goes on the "necessary."

It's cool to hear that phones without cases should be just fine for men though! :D

P.S.: I rarely drop my phone, but I did once shatter a screen by trying to grab the phone as it slid off the edge of a linoleum counter. The glass will shatter easily if it gets hit from the wrong angle — even if the impact comes from a distance of just centimeters.