Why do they keep making wireless trackballs? The whole point of a trackball is that it doesn't move, so a cable is a lot less hassle than it is with a mouse. I really don't want to worry about charging or changing batteries on my trackball.
Much more convenient to use with laptops, or with setups where wires are inconvenient for reasons other than mobility while in use (e.g., any situation where you would use a wireless keyboard, which is also usually stationary when in use.)