Use as a distraction-free word processor is listed as a use-case if you read far enough. (As mentioned, the notes are a bit of a mess and weren't cleaned up for public consumption.)
But, yes, a laptop can do pretty much everything Paperterm can do. A laptop can do everything a Kindle can do. A laptop can do a huge percent of what your phone can do. If the advantages of this niche device (e.g., sunlight-readable display with no backlight/blue-light, it's insane battery life, a no-compromise keyboard, and it's always-ready-"never-off" state) doesn't appeal to you, then you're right, you're probably just not in the target demographic. Those in the target market find a lot to love in such specs. This is explicitly a niche product, not trying to be everything for everyone (which is closer to what a laptop does).
EDIT: if you have a look at the (also not ready for announcement) root of the domain, you'll see a brief pitch: http://www.paperterm.org/ This page also has notes-to-self in brackets, and I'm not in a spot where I can fix it right now, so ignore that.