[Gustomaximus]

In my very limited experience of firing a handgun you shoot with a slight pause between shots to bring the muzzle back down on target.

If you go full auto, I suspect the shooter would find their muzzle going higher and higher so after the first couple shots they are shooting way high. So if they have 15 bullets in the magazine 3 are good and 12 are way off target type deal. Whereas if they were pulling the trigger at each shot they might aim the '12 air shots' more effectively.

Pure speculation but as I said has the feel of one of those things that may be counter intuitive to what you would initially expect.