The cap is not for the power but to save the ESC.

Several functions are done with the caps:
- filtering out the high frequencies of the swtiching ESC
- filtering out voltage peaks produced by induction on the wires and motor coils.
- take the high current peaks to prevent the voltage drop goes to low and with that keeping the voltage on a better level so the FET's are getting enough to get fully opened.


With no caps it is known the ESC can produce more heat which is not good for its life.