Some children enjoy colouring in. Others do not.
If a child enjoys colouring inside the lines and is good at it, great!
Colouring outside the lines? No problem… There are other, more creative activities that give children the chance to learn pencil control.
Personally I believe it is much more interesting have them do a free painting, create their own pictures. Art can be a natural way for children to express themselves and communicate their feelings.