Friends/neighbors won’t get upset with you if you don’t recognize them right away in public. (And also, if you’re not in a social mood, it’s harder for others to recognize you.)
No one will know if you have a bad acne day.
You can silently advertise your favorite movie franchise or anything else with a customized mask (and it’s easier to see than a T-shirt).
You can feel a little bit more like a ninja than usual.
You don’t have to bother checking your teeth for spinach after having quiche.
You might as well go all out at Halloween and dress up like Darth Vader or something else with a full face mask…