Masks do protect the wearer! And you do not need an N95 mask to do this. Even a simple homemade mask offers some degree of protection. This[0] was a good explanation of both of these ideas.

tldr: There is reason to believe that large droplets, not the tiny droplets that N95s are designed to filter, are the primary threat, and any sort of physical barrier between those and your mouth/nose will help.

I see a lot of people saying that we shouldn't wear masks in order to preserve the supply for healthcare workers, but I think this is ridiculous. You need a mask when you go out both to protect yourself and to protect others. A better message is, to preserve the supply for healthcare workers, make your own mask, or use a simple dust mask or a rave mask.

[0]: https://medium.com/@Cancerwarrior/covid-19-why-we-should-all...