Someone go save Sarah Connor

[chitoryu12]

Sea Skimmers quite correct, if the guns were manually aimed and fired, they simply couldn't engage targets fast enough.

Not aiming. Just confirming a target and pulling the trigger. I believe a Russian mobile AA gun (I think the Shilka. It's whichever has the four barrels) has a similar system, where all the gunner has to do is look at what the gun is pointing at and fire.