Another reminder of how easy it is to forget how ridiculously fast computers are these days (especially when you're like me and not writing stuff close to the metal for your day job).
In terms of latency... well... we also could do a lot better there, but as I understand it, even if you do your best to cut away as much software bloat as possible, the latency "floor" seems to be higher than in the old days[0]. And the many layers of abstraction that is the average software stack don't help. Like, I'm doing my best to keep a web-app snappy, but there's only so much you can squeeze out of a browser.
But chips today are much larger and are basically a cruise ship or an aircraft carrier- bigger with more work than a bike. https://www.inkandswitch.com/slow-software/
I meant "time between input and visible change on screen", or lag between writing on a tablet and the screen or eink showing the drawn line. It's not really as crucial when typing, but especially for writing or drawing on a tablet low input latency is the difference between getting in a real flow state or not.
E-ink has had some improvements- I'm acquainted with the developers of this project: https://www.crowdsupply.com/modos-tech/modos-paper-monitor
Refresh rate is only one component of the system- an integrated display controller can lower the latency, and of course, the choice of computer affects the speed as well. Their choice to go with USB-C Alt is a good idea.