The masks serve as a reminder to not scratch your nose, since it is covered. Glasses or sunglasses help for your eyes.
Over here, supply doesn't seem to be low. Lots of smoke recently meant lots of masks in the supply chain. I'm surprised I see so few worn in the shops though, especially since I spent a lot of time in Asia where masks were common during flu season.
So yes, with supply being low, it's far more useful for infected people to not spread said droplets.