Very impressive, but I think running android on these devices make them look even more impractical than they really are. E ink displays have a very bad refresh rate, when you combine that to fancy smooth animations the result is a lagfest. We need to have redesigned interfaces for these type of device.

Speaking of refresh rate, at the end of the video you can see someone drawing on the screen and everything is rendered pretty quickly without having to redraw the entire screen, is that a different technology?

Yeah. It'd be interesting to have something like this tech be used for a project like The Open Book (OSS e-book reader):

https://github.com/joeycastillo/The-Open-Book

Maybe The Open Book v2, or v3. :)