Like real life, you can only really concentrate on one person talking in your distance without being annoyed.
The fact that you can hear everyone at the same volume, everyone wants to comment on something and that everyone might not have decent mic quality could get a bit irritating.
This is why implementing voice chat, or even thinking about it, seems like a really bad idea.
But if people are civilized and let each other have their say with limited interruptions then it can be pretty neat
