Contrary to your dangerous comments, masks do work. As has been demonstrated quite thoroughly by qualified scientists rather than uneducated and uninformed “commentators”.
The primary purpose of masks is to limit the spread of disease from an infected person to others in the vicinity. You wear a mask to protect others, not yourself. If everyone does this then we all remain safer (though of course we are talking about reducing risk, not eliminating it).
For some reason the concept of looking after others, rather than just oneself seems to be quite alien to many.