The why: helmet covers suck. Plain and simple. They fit like crap, slide around, make your head look twice as big. And you can't hang all that cool velcro with a cover. BUT, they do all those things that were originally mentioned. Soften the edges is a very true statement. Soften the sound too against vehicles, structures etc. I've yet to see one on a Ops-core though. I too have heard they exist. Some cohorts of mine would be interested in their covers.