Mask ? of course, I would say, to protect yourself. Against those who have the virus and do not know, yet. Or those, who simply do not care if they spread the virus. Simple as that. Despite that some people may think that masks are silly or are only worn by those who are actually sick.
Since this world-wide epidemic (turned pandemic) has started it was clear that this virus – as most virus attacks are – is also air borne. People walking in the street, talking. Always talking. Breathing and spraying the virus infected air around, or worse, inside closed spaces, head to head, breathing the virus into each others faces.
For me, it was also quite clear that the regulations (keeping social distancing to each other at least 2m apart) is long not enough. From the start, since March 2020, I keep a distance of 5m. In the street, and try hard inside a store. Lucky, I live alone, no other person ever inside my home. Try to avoid public transit. When I need the bus, wear a mask. Inside the store, wear a mask. Washable, every day wash not only hands, groceries, all containers, but gloves, mask, and after the odd bus ride all my clothes.
So, when some one in the street passes me and might assume I am sick wearing a mask, then that is not true: I do this to protect myself from getting infected through the air. Because once infected a virus is in your blood, will travel and multiply. Since we do not have regular blood tests (to test immune system responses to such a virus) or a well functioning health care system to test for the virus itself, or get treatment once one is infected and sick. the only way to stay alive is: BE CAREFUL, PROTECT YOURSELF.