Some members of the general public would also benefit more. People who know they’re sick or interacting with someone who’s sick are already advised to use a mask. People who frequently interact with others as part of their jobs, like a first responder or a grocery store clerk, are more likely to get good use out of masks too. The logic is similar to why masks are so important for health care workers: Masks are most useful during prolonged, close interactions involving potentially sick people.