I'd always advise to do this only on revenges...
I mean, if it's a TH10... okay, he gets probably not as much as you got off him, but he could steal quite a lot of your other resources - and at least I wouldn't want that to happen. Hehe.
^ See my comment above.
Best thing to combine this with is sniping exposed THs. Works perfect.
Take archers or so to take out the TH, then go for the drills. I wouldn't go for the drills first since you might trigger a CC that could hinder you on taking out the TH and losing the battle.

