It is believed that the company The McLoughlin Brothers (en.wikipedia.org/wiki/McLoughlin_Brothers) invented the coloring books. They published a book called The Little Folks' Painting Book in collaboration with Kate Greenaway in 1880.
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.