The flagship foldables have two screens. A screen on the front that’s a full sized screen just like any other smart phone screen of the last 10 years.
But you can then fold the phone open to get access to that wider screen.
So you get the best of both worlds, a normal phone handset for one handed action. But a larger screen for when you want something that’s a little more “tablet” like.
Just to add, I too was originally put off by the crease in foldable displays. But if it’s a second screen then I can actually live with that crease since it’s not something that’s going to affect casual use. It’s just there for when a normal phone screen isn’t enough. So it’s almost like having a bonus screen rather than a crease in your main screen.
The best of both worlds for me would be a device around the size of the "iphone mini", but with a thicker body, no camera bump, and the extra volume is all battery.