I like the concept. I have a e-ink reader where I removed the hull because it's annoying, but at some point I must have damaged the display a bit and now it has a little black spot. With this the added bulk also doubles the area available for text. Maybe not that useful for novels that you read through linearly, but for non-fiction it would be nice to see other chapters, glossaries, etc. on one display while keeping the other at the page you were reading. Mainly a problem of software and enough buttons to be able to comfortably use that.

Though the low-res displays of this prototype look atrocious to me (pixelation and uneven blackness), maybe a later version will improve on that.