Would love to be proven wrong but I think it's going to be a monumental flop in regards to sales.
For me, the biggest barrier right now is price. Having it all in one device is convenient, but for me it would easily be cheaper to just have a year-old phone and a year-or-two old tablet. Hell, given that I paid $400 for my Galaxy S8+, $200 or so for my Nexus 7 (like five years ago), and about $800 for my laptop, I could have all three for less than the cost of this thing.
Again, I'd be happy to be proven wrong - and I do appreciate the engineering involved in making a consumer grade foldable screen.
Even if that's the case I think that's fine. It should help push innovation at Samsung and its competitors. Sure, they should be more consumer focused _in general_ but I think moon-shots like this have their place.
I'm not interested in a fold-able phone. But I'd love to see them get really good.
The screen was nearly as big as the Nexus 7 and fine to read on, in a much smaller overall form factor thanks to the smaller bezels. The Note 3 served all the same needs as the Nexus 7, and it still fit in a front pants pocket like my old phone (which the 7 didn't).
I went from there to a Note 4 and Note 8 and never used another 7" tablet.
What seems weird to me about the Note Fold is that the folding display isn't all that much bigger than the Note 8 - 7.3" diagonal vs. 6.3", albeit in a more square aspect ratio.
OTOH, if anyone on the SF Peninsula buys a Note Fold, let me know and I will buy you lunch at some very nice place just so I can play with the phone. I promise I will try not to break it!
In that sometimes you only have your phone with you. Outside of the normal status-y nature of high end phones, I could see this being valuable to an exec/management as this would allow them to review Excel documents and PDFs on the fly when in situations where booting up a work laptop isn't ideal or possible (laying in bed, at an airport waiting on flights, etc.). In that particular scenario it is putting a gun to the head of work/life balance, but it is a scenario I could see it used.
I'm interested in the form factor mostly for consolidation: with eGPU, I've consolidated my laptop and gaming desktop into just a laptop that plugs into the eGPU when at home and this form factor would negate a real need for a tablet for reading, video consumption, or what have you.
I personally prefer the Chinese ones where the bend is on the outside (mostly because the Galaxy Fold closed seems like an absurd waste of real estate), but I'm glad Samsung and others are working on this. It isn't a problem really, but it eliminates the need for so many different types of electronics if 2 bigger ones are consolidated into one device.
I think the latter is easy to see a market for, anyone who currently uses both a phone and a tablet or e-reader who would prefer a single device that fits in a pocket.
The numbers aren't public yet, but it's probably low. I don't think they are dumb enough to expect this device to sell anywhere near the Galaxy S10 or an iPhone.
It may not be a huge sales success, but apparently it's above Samsung expectations.
My suspicion is that it's people interested in the engineering of the screen rather than consumers who've identified a personal use case for it.
Whether or not it ends up truly being practical, it's a phone that looks and does things that are radically different from most mainstream phones.
People will think their fancy future folding phone is cool, and other people will probably see it and think it's interesting and want to talk about it or see it work.
Kind of like paying $600 plus a 2-year contract for an iPhone in 2007 with a slow processor, no 3G, no MMS, no copy-and-paste, etc.
My guess is that it's for people who want "phablet" to be a realistic description of their phone instead of a hyperbolic one.
Belt clips. Cargo pockets. Purses. Bras. Sufficiently deep front pants pockets. Jacket pockets. Etc.