The rapid-firing rotary gun has had a special place among BFGs. Because it's basically the gun equivalent of a chainsaw, there is an undeniable attraction to a gun which can produce high enough rates of fire to cleanly trim hedges, cut down trees, or, in the case of the GAU-8 Avenger, saw tanks in half. The practical advantage of having multiple rotating barrels is that the heat generated during firing will be distributed over multiple barrels instead of one, preventing overheating.