Assuming you are asking about dynamic, sometimes called ramping, timing advance ESCs, the ESC dynamically and continuously adjusts the timing advance by motor RPM.

Like most everything, timing advance is one of those ‘all things in moderation’ deals. Some timing helps power and efficiency, but too much is bad. Can overheat or even smoke the motor real quick. But the ideal amount of timing varies a lot by RPM (and other factors).

Adjusted correctly dynamic timing ESCs can significantly broaden the power/torque and efficiency bands, over a much wider range of RPMs. May not always seem more efficient, as it will generally use some more battery, but it’s producing a lot more overall power too, making the RC go a lot faster. And quite possibly with less motor heat.

Many can be adjusted for a further timing increase after a set time at full throttle, for an extra kick towards the end of long straights.

Note there is static, or fixed timing advance too. Most motors have some timing built in, some ESCs also. But it’s only ideal in a much narrower RPM range.