1) A mask/covering will reduce the amount of virus reaching your airways - may not prevent catching it, but may reduce the severity of the disease. There is limited research on other viruses in this vein, but not something I'd bet money on.
2) Asymptomatic spread is possible, which means someone who doesn't think they are sick who doesn't wear a mask could be spreading it
3) More and more lately, I'm hearing experts say "it is highly contagious". I'm very curious if they are speaking of the super spreader phenomenon (which I don't know much about), or in general. We sort of knew back in January that it was easily spread - moreso than flu - not as much as measles. I worry that the people at the very top - who can see the whole picture - know something we don't.
As for me, with everyone around me wearing a mask I wonder if I really need to wear one
