Speaking from experience, using sheet metal screws in metal studs only works sometimes. A lot of the time the screw doesn't catch, and if you apply a horizontal

Speaking from experience, using sheet metal screws in metal studs only works sometimes. A lot of the time the screw doesn't catch, and if you apply a horizontal pulling force, you can just pull the whole thing out. We had mounted some closet brackets to metal studs using sheet metal screws, and it held for a while. But eventually the brackets came out of the wall. We went back in with toggles and it's all good.