Speaking strictly about battery drainage, the longer a battery is asked to provide energy, the more energy is consumed. Short pulse fires (pulse discharge rate) will consume less energy and be less draining on a battery. The longer you press the fire button the more energy is drained (continuous discharge rate), draining the battery faster.
For example, you have an ego battery which is about to be completely drained. To save battery life, you'd use short pulse fires to drain less battery life. Longer button presses would drain it faster. That's my opinion.
The resistance or ohm rating of the delivery device plays a factor in this as well. Low resistance requires more amperage from the battery overall because more energy is being pulled more freely from the battery.
batteries do not "push" energy, they simply release energy within them.
When thinking about resistance, imagine water flow in two sizes of pipes. A wide pipe has less resistance for water flow and would allow more water to pass through it. A narrow pipe has more resistance and would restrict how much water passes through it.