It goes off on your next ability or autoattack, regardless of hit, miss or it not even being a damage related ability.

I actually don't think it's consumed on a missed autoattack in all fairness, but it does depop if you press a special (or right click something in your invenotory etc).
But yes, it's way to weak at the moment; could be a smaller buff during a shorter time instead (it's a ~1200 attack in a full party about at rank IV if all use it, so it's not exactly weak per se, even more for every one that's a dot instead of a direct attack due to it adding static amout of damage per tick to it) but it still leaves something to wish for.