Thanks to colorings the child perceives the world pattern, implements its own color discoveries. If a child paints the picture in unusual colors, you should not abuse him for that; it is his own opinion.
In the process of painting you focus your attention on a subject that is at your fingertips. If you do it with enough concentration, it will ignore the extraneous noise, unpleasant thoughts and worries. This is a very useful skill that will be useful in situations where you need to briefly forget about your physical or emotional pain.