Why do art courses always have the child try their hand at copying the art masters?

Great question!  We completely understand that you want your children to be able to express themselves in their own unique ways. However, copying the master artists has been done for centuries. Da Vinci apprenticed under Verrocchio, Michelangelo apprenticed under Ghirlandaio. Basically, they copied their masters' paintings/sculptures to learn techniques and skills. The French Realist and Impressionist painters would go to the Louvre and copy the art of the Italian masters (who were long dead).