Random kink/MC/drone musing ( very lewd)
That said finding other reasons can be fun. Perhaps it works like the Weeping Angels from Dr Who and they do something with that potential mind time. Or the drones literally time share their minds to augment others.
The later- well that might have side effects. Having a drone make your brain run faster is useful up until the continous sexual need it feels starts leaking through and then, well I think we know where this is going.