For swingers, a great tool IMO.
For putting, the putter is amazing. It can teach you more about putting in a very short time. Off center hits prior, at and post center, what and why. Putting strokes that work on short putts but don't work on long putts. It is by the way the most own club by pro's. The difference between straight back and back, up and in is an interesting test. Same stroke, adjust your posture and wow, it show why you need to be consistent, cause it doesn't take much adjustment to impact your stroke.
If you find someone who has one, try it. It can be a real eyeopener. Oh, I don't believe they make it is the belly style yet.
Back to the other clubs, they have some excellent drills and methods to start from square 1 and work up.
What is missing IMO, is the basics of the swing, this you need to bring with you, but be prepared to change cause you might have some faulty knowledge.
It is not a replacement for an instructor.