It's probably a habit thing, like the yelling. I find that I've gotten into the habit of grunting a lot when I weight train, I have no idea if this helps or not, all I know is that it takes mental effort to stop myself and when I'm that tired I just don't stop.
So my guess would be that if you aren't used to doing it and you have to force yourself to yell like a madman then it'll just hinder you.

I don't know what level you're at with the climbing but it honestly doesn't sound like something that works if pros aren't doing it. The edge is all in your head and if you enjoy that, then go for it, just don't die. Well I don't know you so I guess I don't care if you die... yeah : D