I suspect they’re showing off, like people with flip phones did back in the day. I doubt I’ll ever get one myself because of lots of reasons, including thickness, vulnerability of the screen and mechanism, the fact that I don’t like a crease down the middle of my screen, weight, extra points of failure, water ingress and dust, plus others I can’t remember.

Some people like em. That’s cool. I have an iPad for when I want a bigger screen, and am cool with not having it with me all the time.