Not sure about this one, but it depends on how you program it. If you program it like an led, it’s horrible. But if you do it properly it’s pretty fast. Animations kill the refresh rate. You can draw a new screen and refresh the whole screen in like half a second. But if you do something like a button animation where you change the color of the button then back then refresh the screen, you have three changes which can take a second and a half.

So, yes, if done well, you can send and receive messages on e-ink fairly well.