Many people don't know they are infected and also there is not enough testing capability in many countries. For example Heidi Klum tired to get tested after catching a cold and it took her several days to be accepted for a test. Now she is not exactly your average Joe and would be willing to shell out a few 1000 dollars to get tested.
Unless that situation changes, masks are a good alternative. And yes, only if everybody wears them.
Unless that situation changes, masks are a good alternative. And yes, only if everybody wears them.