As was said in one of the links, the degree is for artists who want to teach, and if the degree provides a grounding in pedagogy, then I'm all for it. Being an artist doesn't necessarily qualify you to teach art. Perhaps to run a master class, yes, since all that requires is for you to pontificate about yourself and the greatness of your art, but to actually teach the subjects of art, no. Teaching is it's own skill, not easily come by, and some education in that direction (perhaps even leading to a Ph.D) would be a valuable thing.