e-ink is a weird niche tech IMO. The room required and case/screen protection would be the same as a typical OLED display. So why would an e-ink be better than a full functional display?
The only time I think e-ink's are really useful outside of book readers is for situations where data refresh rate is seldom or battery life is critical and long microcontroller sleep times can be leveraged with the display still showing information without power for a very long duration.