Seems like an expensive solution to the drone boat problem. I would think a 50 cal burst would do the trick.
Guns run out of ammo. If this isn’t a chemical-fueled laser, the laser can fire as long as it has a sufficient power feed.
Also, it’s kind of trivial to armor a boat against .50 BMG these days, if only on the frontal surfaces.
In alot less time that it took that fancy laser to down that drone, one 1/4 second burst from a vulcan would have obliterated it into cloud of tiny vaporous pieces.