US news keeps telling average people NO NEED to wear masks for coronavirus, but I see on TV that when Chinese/Korean/Japnese go out to the street, all of them wear masks.

If the US advise people to wear make later on, we don't have enough supplies anyway. Because we don't have enough supplies. What's your take on this?

Also, if mask doesn't work, why I see emergency people wear mask all the time then? Doesn't wear masks reduce my risk?

Also, what's the correct Western perspective on wearing a mask? Will people look at me differently on the street if I wear a mask?