The ultimate poseur accessory! Once upon a time a wheelie was the result if a failure to balance wheelspin and traction and the outcome was a poor run. The guy who did the big wheelie was the big loser.
Don't get me wrong. I like to lift the front wheel under hard acceleration as much as the next guy just to let my B 1200 "flex its muscles" but roll-on acceleration, not the wheelie is, the goal. The wheelie just happens.
The big long wheelie is just a stunt. One might just as well learn to ride standing on the seat etc. to show off for the easily impressed. I have no doubt that this gizmo would work but I would rather spend my money on more horsepower, gasoline, tires, etc.