I get that you're talking about situations like typing into a remote terminal, but this technique still causes eye strain which brings us back to square one with slow eink displays which are like this all day long.
I was talking chiefly about typing on EPD :) (Soooo many keystrokes, so many hours.) I personally felt no eye strain - it may depend on your ability to adapt into the process.
Way back in the day I remember using a terminal (TeleVideo maybe?) where the characters just sort of faded in as you typed. The latency was really bad. But I got used to it pretty quickly and didn't find it really bothersome.