It would be fantastic to be able to bring my laptop into the sunlight for work. And with the expectation of greatly improved battery life.
Edit: Ooh, I found Liquavista: https://www.youtube.com/watch?v=D6tzaIgZKs0
Edit2: And Electrowetting as well: https://www.youtube.com/watch?v=Bf1GjCaYzYg
Hmm, why isn't this in use.
OLED was hung up for years because the blue pixels had 1/100 to 1/10 the lifetime of the red and green one.
In addition, you would be stunned at just how good our visual system is at picking out imperfections. Anything less than perfect (especially involving green) will produce complaints.
After both of those, you can talk about cost and efficiency.
And I think you're point is on point: people would buy these and not be happy with them, because they want a real monitor. There's also a group of people who want them just to be able to ready articles and write articles (and code, etc) outside, and without charging a battery as often, and would be happy with lo-fi graphics.