Ok so taunt appears normal to pyro taunting regardless wearing the cosmetic pyrovision or not. But to other players they must wear pyro vision to see it or they will see a pyro riding his flamethrower. Also the noise it produces is different like the appearance of it to player. Like to normal non pyrovision players (except the pyro taunting) they hear pyro laughing but if pyro that is taunting gets a horse neigh while riding it or not.