The response time for individual pixels is quite slow, around 250ms. It takes that long to apply the necessary sequence of voltages to get a clear image without

The response time for individual pixels is quite slow, around 250ms. It takes that long to apply the necessary sequence of voltages to get a clear image without visible ghosting. That slowness is an obstacle even if you had no bus limitations. Something like the loading indicator might be moving faster, but ghosting is acceptable for something like that. I wrote low-level software for E Ink displays years ago, when the practical response time was more like 400ms IIRC. At the time, drawing lagged too much to be pleasant for a consumer device. Maybe now, if you do something clever with a quick 1st pass and a slow 2nd, darkening pass, you could get a reasonable result... Maybe.