Why perk it? Because it'll be about 8x easier to get kills at any given range (in the air or on the ground) than the 37mm variant, it fires probably a dozen rounds a second where the 37mm does about 1 per seccond (maybe 2 for every 3 seconds?). It will be able to lead targets far more easily than the 37mm because of this volume of fire, and any hit could still do critical damage to the average fighter plane in this game.
About equal power (any hit is gonna hurt, bad!)
Multiple guns
Much faster rate of fire
Solid wall of lead, any one of which gets the job done
vs single shots that targets fly THROUGH rather than IN to, as on the 37mm.
It'll be like flying a 109k4 (osty) then switching to a C-Hog (Wirble)
THAT's the general thinking on why it might be perked.