That's the magic of transducers, they work really, really well on a device that you are also moving with since it's entirely pressure based, not requiring any displacement or movement of your thumb.
That microforce controller I posted earlier is typically mounted on the handle of camera tripod so you can grip it to operate the camera and still finely adjust the pressure on it.
FSSB users can also attest that there is something really amazing about pressure based analog control.