I've never understood the mobile form factors between "Fits in a normal pocket" and "Fits in a messenger bag".
Most of the time anything in that range just feels like compromising tons of stuff just to be more marketable. Why keep making it smaller? It has to go in a bag either way, and in that bag the girth and weight of the device don't matter anywhere near as much.
The only obvious use case I can think of are, devices in which need to be actually held in the hands. Older "lightweight" laptops used to have little sticky out-y batteries in the back that were great for holding and were just about light enough for any sane use case where one would want to carry it around in the hand. For handheld gaming consoles, I think they'd be better off pocket size as well as being clamshell. It's so dang nice being able to just close the thing and put it away in a couple of seconds. No worrying about saving or pausing or whatever just instant stop no matter what I'm doing with basically zero delay. Back into the pocket it goes. If it's not going to be that mobile, that utterly trivial to pull out for 5 minutes waiting for a table, I can probably carry around a controller for it and set it down on something. At which point, it should just be a laptop.
