Reliability, generally. Consistency, afterward. Cost, third.

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.