The first time I did this was many years ago when attending Lee Sparks original Total Control training. I was wearing synthetic gear and he was nice enough to loan me a pair of strap on knee pucks to drag knees while doing figure eights. It's not a maneuver and skill we need in parking lots or the street, but it will improve our balance, control, and confidence. Most riders don't perform stunts like wheelies, stoppies, standing on the tank/bars, riding sitting backwards, but for those who do, the skill developed will also improve their balance, control, and confidence, all of which improves their skills during normal riding. Like dirt bikes and trials bike, some skills are the same some additional skills are required all of which improve our balance, control, and confidence for street riding. It's not for everyone, but I don't know anyone who has tried these skills who didn't enjoy them and they gained a lot of skills that they would never had developed otherwise.