I have seen this drill recommend quite often. I forgot what the drill's purpose is. I am not good at it myself, but on one of the ranges that I use I sometimes see a golfer who only has one arm (which he employs as his lead-arm), and he can really get the ball out there. It is a joy to watch. I am not sure what the story is behind his handicap, but it always gives me a boost to see the guy make the best of his unfortunate situation.