In 3-4 year old kids are more confident in coloring. They're not trying to draw freely, and act within the circuit, trying to repeat the figure bends.
There is no artist, who would buy their children coloring books or taught to paint pictures. What does this mean? Coloring is a kind of framework, hindering the development of the imagination. They contribute to the formation of habits of the finished drawing, in which a flight of fantasy and free creativity is almost impossible.