Hi, Coloring pages can be a great supplement to other learning, and has benefits on its own as well. Here's a teacher blog post that references some of the benefits of coloring pages:
http://www.preschoolplaybook.com/2008/12/benefits-of-coloring.html

In the example of the golfer coloring page, the child can use his/her imagination to draw the ball in flight. He/she can experiment with colors, and practice coloring 'in the lines'. The child could learn golf outside at recess or as part of a sports program, and then color this page inside the classroom to wind down from the exercise and outside activity. This coloring page could help a child who loves sports, such as golf, practice or 'exercise' his/her art skills too. You could also ask the child to write a story to go with his coloring page. I believe there are many ways that a coloring page can support learning.

Thanks for asking!