I personally am not a big fan of VR games that have voice auto-enabled. While I have met many very nice people in VR, I am not always in the mood to talk to strangers. That is why we decided to make Voice Opt-In in ViKubb.
To compensate, we build an easy Emotion System allowing you to display a fixed set of colorful emotions to your Opponent. See it live:
It is of course possible to enable Voice Chat, however it has to be requested by one and confirmed by the other (which is just 1 click for everyone).