What jitter clicking does to the switch
The arm is locked tight enough that its own tremor presses the button, which is why the rate is high and the control is poor. Practised jitter lands somewhere around 450–700 CPM, well above a single-finger click and below a clean butterfly.
It is also the technique most likely to hurt you. The tension that produces the rate is loaded onto the forearm tendons, and holding it repeatedly is how people acquire a wrist problem from a browser game. Short intervals, long breaks.