It is essential for an artist to be a master craftsmen. To be able to have complete control over his medium. It does not mean he has to be able to do everything or know everything in his art or all aspects of the craft or technique of his medium. For example, just how many types of films, developers, papers did Weston use? What did Steiglitz say, less is more? Or was that Weston. But to be able to control what he does so as to create freely, intuitively, spontaneously, no matter what the circumstances.
Control is essential for creativity. To go out shooting with the mentality of the more film you expose, the greater your chances of getting a few shots that are worth keeping, showing, is not the thinking pattern of an artist.
Just because someone is a master craftsman, does not make him an artist. I have watched marvelous furniture craftsmen carve, chissel, sand incredable pieces. But they are reproductions. But to create an original design, brings one more into the realm of artistry.