We may see an increase in PFs stating "Mic Only" or only certain languages. Granted the latter one happens a bit anyway like in the Japanese datacentres (you will often see "JP only") and occasionally there are "Discord Mandatory" as opposed to "Discord Available" postings but really there isn't much content in the game that actually requires voice comms to begin with.

When would voice comms be available, only in parties or only in duties? How could the GMs monitor things said over mic? Unless they are allowed to record everything, which I doubt anyone would agree too plus it would take up a lot of unnecessary data. There is also the possible language barrier as well in some instances (the chat auto-translate can only do so much), and it needs to work for console users. So a few obstacles there that would need to be considered to make it even viable.