One must practice, practice, practice to get better. We sometimes forget that principle applies to the making of images. Before we ban clip art, we should know what it is. Adults who put together books, magazine articles, and television programs don't do everything themselves. They divide the labor.
Editors buy writing from writers and images from artists.
Clip art is faster and easier than doing it yourself. But we are educators, and we have to keep our eyes on our educational goals. Even though we are interested in the end product, the process is just as important. Education is about learning and teaching, not saving time. My experience shows that children who make their own images learn more.