@foone Honestly that would've been the move back then.
Low power consumption, MUCH better contrast, Actually visible in sunlight, about the same resolution, and the framerate on even the last couple generations could easily be done on eink.
And they didn't usually have password locks, so just drawing the messages to the screen as they arrived would've been so good for being able to peek at it without needing to actually do anything.
Honestly eink displays would be amazing for dumb phones. But even today's "dumb phones" are running a slim android backend with full navigation support and everything.