Do any of the folding phones actually work well? I still haven't seen one in the wild (admittedly, I'm not living in a tech Mecca these days)

I've had the past three generations of Samsung folding phone (4,5,6).

My use-case is for travel, where I want to read books, and the very occasional time when I want to do some design work outside the office -- draw a diagram that sort of thing. A third rare use case is where a web site is buggy or limited in functionality for mobile browsers. In all these cases the unfolded screen allows me to do the thing I need to do without carrying a second device (tablet, eReader). Another marginal use-case is to show another person a photograph. The fold out screen is much easier to see and I think has better color rendition too.

For these use-cases I find the folding phone very worthwhile.

But...the benefit that trumps all that is that the phone itself is smaller (narrower) than the typical flagship phones these days. It fits in my pocket and my hand reaches across it. I'd never go back to a non-folding phone for this reason alone, even if I never unfolded it. In fact I almost never do unfold it, except when traveling.

fwiw it wasn't until the Fold6 that the "cover screen" typing experience was ok. I understand that the Fold7 is a bit wider and so probably better, but I can't justify the expense to upgrade so will sit out until the Fold8.

Tried the Fold on a Google event and it was really nice. I would get one, but I don't want to spend so much money.

The Z Fold 7 I tried works so well, I tempted to move away from Apple for the first time since my Galaxy Note 3.

they do work well but are fragile. I broke one by gently closing it on a hot day (about 100F). Saw another break from the kind of short fall that used to break phones before they all got gorilla glass.

I guess if you're the sort that is not clumsy and you're in a mild climate you might get your money's worth

for reference these were Samsung Z Flip devices

The vertical fold ones might be better. I had the newest Samsung Flip (horizontal folding) and the screen died twice. Both times from a small rupture on the seam. The tech at the phone place said it happens constantly, and it costs hundreds of dollars to replace out of warranty.

The google folding pro works really well