When you need to kill someone who was just res'd and need to penetrate the over shield you'll care about impact a lot.....
English
-
I can't say I've ever been in the situation of having to put another warlock down after self res with a sniper so really your better off going with the better perks over impact cause all snipers are 2-1 hit kills
-
Or you can double tap. The revive animation is more than long enough.