Comment by mcsb4

> So if you are infected and not showing symptoms ie. not coughing/sneezing then arguably the mask is not doing anything.

It prevents you from touching your mouth and your nose and thus getting it on your hands.

There is an excellent video visualising the spreading of germs:

https://www.youtube.com/watch?v=I5-dI74zxPg

How To See Germs Spread (Coronavirus) by Marc Tober

Maybe that convinces you.