Curse Voice lets robloxians talk between each other (like actually your voice) You do need a mic, but another idea is that in games if somebody also has it, you guys can join a call (or leave it) and strategize (like 2 teams)
ROBLOX had said before this would never be implemented. They can't moderate what goes on the headphones; even friends fight. If you want to strategize for a game, I would suggest making a party or using (TEAM CHAT).