[imtringued]

The primary benefit of high rate of fire is hitting a single moving target. Machine guns used to be particularly common in air to air combat. When you are a school shooter or bank robber you actually don't want to waste your ammo like that. The downsides of reloading are by far stacked against you. A soldier can just go back to base and reload his guns but a robber whose magazines have run out will just see his targets flee and his only opportunity slip away.