Given reasonably careful distribution, it’s possible to finish a whole battle this way in a single turn.
The above might sound simplistic, but it’s just the tip of the iceberg.
Barrelmancy is a practice - dare I say, an artform - that goes back toDivinity: Original Sin.

Go on, see what kinds of mischief you might wreak with them.
Then report back here, so I can do the same.
