What is the use of tapping headphones?

The factory default settings of the earphones are as follows:
Tapping any earphone twice to answer an incoming call;
Tapping any earphone twice again to end the current call;
While music is on, tapping any earphone twice to pause/play;
At any time, tapping any earphone once to turn on/off the ambient sound monitoring;
If you want to reassign the tapping actions for the earphones, open the app and modify in Profile > Amazfit PowerBuds > Gesture settings.