Can anyone explain how ignition timing is advanced in our cars?

I understand that the hall effect and shutter wheel mechanism is used to generate a signal input to the computer and therefore records ignition timing.

I have also read here that the computer's only ignition timing related output is grounding the coil:

https://www.autozone.com/repairguide...00c152802514de

Supposedly, based on how the coil is grounded on and off, the ignition timing can be changed. However, this doesn't quite make sense to me.

If ignition timing were solely dictated by the time at which the coil was grounded, wouldn't the position of the rotor only need to be "somewhat close" to the plug wire its igniting? If this is the case, why does physically rotating the distributor affect timing at all?

I do not realize how the computer's outputs are capable of adjusting this timing. If anyone could elaborate, it would be much appreciated.