At that price, it likely wouldn't be e-ink. But even more so, the framerate of e-ink tech currently on the market isn't suitable for moving graphics. There are a few companies working on different ways to solve this problem but the existing e-ink patent is quite a thorn.

The demo was definitely not an e-ink screen, but then again, it was a simulation so who knows for sure.

I tried to find battery specs on the page but couldn't.

I think it would add unacceptable weight. And the mechanical stress would probably cause a redesign of the whole product. You don’t want the screen to crack the first time your 8 year-old gets a little enthusiastic about winding it.