I use mine to weaken prize adventures

All the above?  But in priority, to capture and hold targets.  Often times the more veteran players will play ping-pong over a target (talking to any newbie reading this). 

Any left overs for the day go into engaging Defensive prizes.

Aye Dark Corsairs arrrr really good for capturing Targets.

By the way they can also swab down the decks pretty well. Yo-ho-ho!