It's a pretty excellent application if flexibility can be solved. The issues with color in e-ink boil down to having to float more kinds of ink dot, making it

It's a pretty excellent application if flexibility can be solved. The issues with color in e-ink boil down to having to float more kinds of ink dot, making it slooooow. But instantly changing to match surroundings isn't ideal, because it's change, and change is what we notice. Granted that if it could change instantly then that process could just be run slowly, but it seems like a lesser disadvantage compared to any user interface.