I have seen numerous doctors in Korea and China (not the government) say that masks are extremely important. Any kind of mask in general public (obviously not hospital environment) greatly reduces the chance for casual human-human spread. Besides government mandates, its a kind of social shaming as well.
Also, scientists and government will never have clear knowledge and information on this disease until antibody testing is widely available.
Only from that will we find out how many people really had it, and what the real “R0” transmissibility is, and under what particular conditions it spread. Policy makers now seem to be operating under extreme “worst case” scenarios.
Unfortunately, that will likely only be possible well after the present crisis has passed.