The best things about GK is the skills built are easily used and improved on in many different situations. On road, off road, hazardous conditions, or just going for milk, you will feel more confidant and relaxed in tight turns no matter the obstacle.
Off road I've noticed several times there was better balance, better smoothness, and a sweeter line after lots of GK practice.
Its doesn't have to take 4 hours out of your day either. An empty lot, field, or trail is a perfect excuse to slip the clutch and drag some rear (brakes) to find a happier riding position and where the traction really is.
I wouldn't suggest using bricks with street tires ;-) but it works well to reinforce balance on my drz.
Try it out. I promise you'll like it.