Energy orb and it's uses.

Barrage+ds > spam ds unless you're on multiple targets, or if your barrage is too low. Max barrage + DS is better than spam DS, I'm almost sure.
Then again, if you use orb at zakum, then you might hit 6 arms.

I meant is level 1 barrage + max DS > spam max DS. Assume single target, since it'll only get better on mobs. I'm damn sure spamming is stronger. :/

Hitting 6 mobs is the point, yes. Though if you can hit 4 arms (which is pretty easy with it's range) orb is useless. If you're hitting 2, you're better off using demolition. If you're hitting 3 and dragon strike can only hit 2 of them, orb is best.