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.
Lugging around a full KVM console is overkill (unless it is literally on a cart and you only need it at one location). And USB crash cart adapters are buggy, overpriced, and unmaintained.
With serial, SSH, and KVM this will fill the perfect "there is a piece of hardware on the rack I need to interface with" role.
I could understand the no-distraction writing i.e. word processor use-case that some people think E-Ink would be good for, but that doesn't appear in your list of possible applications either.