Of all of the colors, why is blue so special?
It is one of three primary colors along with red and green. These form the RGB color model
What is it good for painting?
Arists used it to paint windows of churches and cathedrals in Middle Age Europe
Why is the sky blue?
This is based on an optical phenomenon scientists refer to as Rayleigh scattering
Is there enough blue in the world?
Yes, after all, it is one of the traditional three colors in RGB