Jst droneing on

[Suicide Junkie]

Well for one thing, they don't cost maintenance.
During peacetime, you could build up quite a stash, and never have to pay a penny once they're built.

You can use them to kill small decoy enemies instead of dividing your main fleet to chase them down.

They'll do pretty good as WP scouts, too. Inspect the defenses, see what kind of firepower you'll need to win.
WP assaults would also be a big advantage to the drones, since they'd start out mixed right in with the enemies.
The PD will only get one shot, and by the start of the second combat round, almost all of the surviving drones will hit their targets.