I never balanced a tire on a motorcycle up til about 10yrs ago and never had a problem. Once I bought a decent balancer and have nice balanced tires I can't say I can feel any difference or get higher mileage, less cupping or anything else.
The thing I thought was kind of interesting, I mounted and balanced the big rear wheel/tire on the Goldwing and it took near 2oz to balance, then after the tire was worn out I thought it would be interesting to see if it was still balanced. It was 2oz out of balance in nearly exact opposite side, so removing the original weights returned the balance to nearly spot on, so balancing at mount does not mean it will stay that way forever. Despite this, of course I never could detect the balance had gone downhill over time. This is where the beads are supposed to help and constantly balance the tire, but my mind goes by logic, and can't quite logically imagine the beads doing much of anything.