When you give somebody a chat ban all you're really doing is preventing team communication. It's pointless when you can mute people in game if they get on your nerves. So really there is no reason for chat bans at all. good try though i guess.
Interestingly, it seems that most of the "team communication" from players with chat restrictions tends to be communicating who sucks and why. Which aren't exactly useful pieces of information.
Besides, the restrictions allow for some amount of communication, which lets them become a useful tool for learning how to use chat effectively.
Additionally, it turns out that most players with chat restrictions (at least in the first wave) actually saw their win-rates increase, which tends to indicate that their form of communication may have actually been holding them back.
