it does not matter in practice, let's say you do a full refresh once a second, it would take more than 11 days to do 1 million refreshes, if you do full refresh once a minute, it would take 2 years
Those numbers don't seem high, at all, for me.
Typing would probably cause a refresh more often than every second and even if it's delayed to be once, every second, it's still only 11 days.
For the usage being discussed here, 1 million is extremely low. For its original intended usage, which might cause one to dozens of refreshes per day, it's more than it'll ever need.
For eink reader is more than enough, for digital typewriter eink is not good choice for display, there are high contrast lcd displays with in-pixel memory that can be used
