I don't understand why people ever play with voice chat enabled. I don't want to hear streams of ungrammatical foul language, and I certainly don't want to hear people slapping their kids, etc. TMI.
Maybe the other players were just really good and I was getting carried? But from my anecdotal experience, good voice chat tends to add a ton to team momentum.
With someone who's playing TV in the background, someone who doesn't bother with callouts, and someone who's tilting hard... I'd rather mute them and myself.
Heck, even a "casual" MMO like PvE Guild Wars 2 games, have chat-rooms and voice-chats because its way easier to specifically say "My Rocket Boots are charged, can anyone drop a light circle?". And that's not even truly competitive or "hard" compared to FPS games.
Go into PvP Guild Wars 2, and you won't get anywhere without voice chat. Coordination is a huge element of the game.