Imagine being at the gas pump, and the person next to you sprays gasoline at you. A faceshield might keep your face from getting soaking wet, but if you smell the fumes, it hasn't prevented exposure to your sinuses or lungs.
I'm hoping Doctors aren't being hosed down with concentrated gallons of trillions and trillions of virus. PPEs aren't going to do much in that situation.
Except you can't smell a virus.