Trust me, the stuff you can do with this technology is amazing. I suppose there are similarities to video if you have a video setup with every camera angle imaginable and have a live feed in front of the student to watch what is happening when they move. How many teachers here have a setup like that? Not the most practical and certainly not portable among other noted limitations.
Some might need to see the overhead view to watch the hand path from there. Some might want to see the DTL view. Keep in mind that the visual feedback is in conjunction with the "feel" of doing a move properly. Trust me that it is a heck of a lot easier to troubleshoot doing something wrong when the player can experiment with what they need to do to match the "mesh" from every angle they want to see. This is just a small piece of using 3D feedback to train.
As for using it to train proper pelvis/thorax etc movements... sure you can get close without it if you are an exceptional teacher and the student and you communicate with each other well, but you can do it faster and better with technology like this. A good analogy would be a body builder preparing for a competition by zig zagging calories up and down each day and by eating precise ratios of complex carbs to protein and fat, but not being able to measure anything, having to "eye it up". Could you get in pretty darn good shape that way? Surely, but wouldn't it be easier to actually measure and adjust if need be? Think many serious competitors would take that approach?
What about laser rangefinders? You can eye up yardages and some people are better than others at doing so, but the best in the world certainly use them to help map out courses. Why guess when you can measure?
