Yes voip is optional when it’s on by default, use it or don’t use it.
The issue of VOIP isn’t just you using it, it’s hearing other people, so the whole “use it or don’t use,” advice really doesn’t comply here, since if you have it on, you will be playing games where EVERYONE has it on, so even if you choose to not use it, everyone else may not.
You’re argument of “having it hidden” implies that players, who never used VOIP or possibly never even heard of it, are going to be scouring through the menus searching for it. I hardly think that players that use VOIP (like yourself) will be so discouraged at having to check a box, that they will just to not bother with altogether.
I also find it comical that some members on here make it sound like having it off by default, (not even disabled completely, just off) spells Armageddon for the FPS genre as we know it. Like the entire teamplay aspect of the game will come crumbling down like the walls of Atlantis. If players are so incompetent, that they cannot work as a team without actually communicating with each other, perhaps it’s not VOIP that’s the problem…Like Nail said earlier
VOIP may make things more convenient or easier, but by no means is it something so crucial to gameplay, that not having it enabled from the start, is going to “cripple” the game, especially since the main reason for them keeping it off by default in the first place, is because it can ruin peoples game experience.