I could only imagine using it for teaching, to replay lessons and see what the left hand is doing, but it’s no different from simply recording. If you were playing in an ensemble, this would be a distraction perhaps as much as a help. I think we are best off not relying on technology and sharpening our systems. No doubt, though, somebody will come up with a clever way to use it. There are harpists who have to play offstage and need to see the conductor and vice versa.