I'm on iPhone now and I've "regressed" back to a relatively normal phone size with the iPhone 7. I almost got a Plus but I had an iPhone 6 before that and got comfortable with the smaller size. I'd probably be fine with the SE at this point, but since Apple has dropped that form factor I'm not going backwards.
So yes, I can see a place for a folding device when one needs to carry both a phone and a tablet, but for me at least, I can move to a phablet for that.
But I do sometimes have a use for the large screen on my phone, and I would definitely have a use for a smaller (one-hand-sized) phone screen, so having both of those available in one device appeals to me.
https://www.theverge.com/2019/4/19/18498904/samsung-galaxy-f...
My cynical side says that this will probably doom the whole idea of a foldable phone. The manufacturers want us to be distracted and spend that half an hour scrolling social media. They want us to be sucked in to using it constantly. They don't benefit from encouraging us to only use our gadgets when we've deliberately decided that we want to. And so it seems likely they'll kind of forget about this once the novelty wears off.
What effect this has on your desire to purchase and use devices is up to you.
"All this week, I kept coming back to a thought about how we use our phones. We pull them out to check something quickly, but then, all of a sudden, a half-hour disappears scrolling Instagram or Twitter or whatever. It’s a real problem.
But it’s a problem I didn’t really have with the Galaxy Fold. When I was using the tiny screen, I just wanted to get something done quickly and put it away because the screen was small, and I wasn’t in a place where I wanted to unfold it.
On the flip side, when I was using Galaxy Fold unfolded, I was really using it. I had to hold it in two hands, and it felt much more like using a tablet, an active device I was choosing to use. It requires some small measure of intentionality — more than a phone, anyway.
I found myself using it in meetings, and nobody batted an eye. I was reviewing docs for the meeting, but I could have just as easily been messing around on social media. But think about the social rules of a work meeting: somebody messing around on their phone is a jerk, but somebody using a tablet is more likely to be doing something relevant. The Fold feels like a different device with different social rules, and that’s fascinating."