Supplement teaching with books? Hmmmm....
It is a common practice throughout the world, especially in formal education. If we could not research and explore diverse opinions and views, we would be stagnant in our development.
True, but books are not so omnipresent, nor so obviously useful, when learning _physical_ skills as opposed to _academic_ skills. So the answer to the question there is not as obvious as it might seem if we were talking about learning history, or math.