Smooth acceleration: The T belt has the advantage of putting down the torque of the engine much more smoothly and gradually than the chain drive counterpart. Using a belt driven motorized bike you won't feel a sudden tug when you twist the throttle, just smooth acceleration.
Easy to maintain and clean: T-belts also do not accumulate dust or dirt and need far less maintenance - like lubrication - when compared to chain driven design.
Little noise: No more noisy metal chain. The belt driven design emits very little noise while in use.