I thought the same thing once. And then I actually used one.
I really did consider getting a folding phone. But instead I decided to get a new Galaxy tablet 10FE, 10.9" screen. Recently it was on sale. I take this everywhere just like I do my phone.
Bigger screen, a lot less money (like 25% of the cost), pocketable too, no moving mechanism to worry about it breaking. And the best part is I have two separate screens, so I can run two use cases at once, where you can't do that on phone or not as easily or convenient.
Like I said I'll be interested in a folding phone when they can come up with minimum 16" screens.
I have a few friends who have folding Samsung phones and they've all had problems with it. Mostly from the moving mechanism. Or dust gets inside and damages it.