Typewriters have some psychological usefulness. It's single function-focused (writing.) And objects which have strong emotional value can be very desirable too - hop over to Instagram.
And this one .. can be easily slipped in the pocket, like Nintendo DS.
With e-ink, even better. Longer battery life too.
You might be able to hook it up to a larger monitor.
As for printing. Micro-printers aren't new, some are as slim as rods. Abhorrently expensive though. Or alternatively that Polaroid pre-inked paper. Or just wireless printing.
One of the best advantages of storing writing in a computer is preservation. And if there's a tree-like elegant notebook installed (CherryTree is quite nice) even better.