I'm pretty sure health care workers wear them primarily to protect others. This is what my health care worker friends have told me (long before covid). Sneezing on someone mid surgery would be pretty bad for the patient, not really for the surgeon.

I think the reason people say it's more for others than yourself is because it's actual pretty rare to catch a disease by breathing it in. Much more often you catch it when it gets on your fingers and then you touch your eyes/nose/mouth. I think that's still at least partially true with covid.