It's simple - writing on the screen with a stylus is a perfect use case for e-ink screen because the latency doesn't really matter that much (I mean, the threshold where it becomes unacceptable is much higher) and you're just drawing on the screen as opposed to moving something that was already drawn there. I have played with simple drawing apps on a jailbroken Kindle many years ago.
Mouse requires low latency to be useful as a pointing device. Do the exercise I've outlined in my earlier comment and you'll see for yourself why, really.
That said, this Dasung screen has a really impressive latency for a e-ink screen. DAW work would still be tiring with it, but it feels like it's already unlocking lots of other possibilities (even though those fast modes leave lots of visual artifacts, but that's to be expected).
Despite looking plausible, I think it would actually end up more straining on the eyes than just an lcd. Maybe in a few years...
Edit: it’s interesting, it looks great when he’s writing on the screen with a stylus. Wonder why a mouse would be so much worse.
Edit 2: this is what a dasung monitor looks like scrolling, mouse cursor etc: https://youtu.be/5pevlmk5kQs?t=655