Come to think of it, such a system would be expensive.
You need powerful, light, smallscale reactors or comparable power sources (ultra caps, batteries) on each of them to supply the turrets, since they are not connected to a ships main reactor. The power doesn't have to last long, unlike autonomous freeflying turrets for station defense they are not deployed for months on end, as they could recharge or refuel at the end of the engagement with their marouder mothership, but they need to pack quite a punch to be useful. Each of them.
This isn't something I could see the collective implement. Their preference for projectile weapons would make this unsuitable, as throwing mass around implies recoil. Since the turrets would be too light to absorb that with momentum, like a large ship, they'd have to expend an equal amount of reaction impulse the other direction as they are generating with their ammo. Highly inefficient, since you now add propellant tanks and comparably large thrusters.
Missiles (as guided rockets) are also recoil-less but then you have the issue of limited ammunition supply and it gets even more expensive (also you could simply launch missiles by the mothership and have them spread out before getting a target coordinate - same effect)
But plasma turrets do make sense. low recoil, high yield, significant tactical advantage. If I were a pirate, had enough money, were flying a marouder, and were high enough up the ladder to "have enemies" - I'd get some drone-turrets. It's a well invested life insurance.
If you're just hunting prey, you simply don't deploy them, so they don't slow you down. If you get into an abush or someone jumps on you, you deploy the field of turrets to cover your back. And if things get real bad, you can set the turrets to auto (although that might be an illegal upgrade, but hey ... pirate), jump out and leave them behind as a deadly nuisance