Tried them on my 4x4 and they were ok for a while but you really need to use a dried air supply or else they get damp and start clumping which becomes worse than not having any balancing (don't ask me how I know).
Just recently had them all cleaned out and balanced normally and smooth happiness has returned.
I have also swapped tyres around by hand with tyre levers on the Landrover, worked up quite a sweat doing a set of 5!
Not heard that, the balls are tiny so getting damp would be a problem..
Motorcycle tyres are a bit easier , they do work well on bikes But bike tyres are usually done in 1500-5000 miles depending on compound.