This is a pulmonary infectious disease. Meaning that the virus is airborne.
If you are infected, then every breath you exhale, every laugh or word you speak, every sneeze or cough you make, can transmit the virus into the air, inside the room that you are in. And it may take 3 hours before the virus particles settle on the ground.
And you don’t know who is infected.
The only way to be safe, and conduct some sort of normal transactions in public, is if everyone wears a mask while in public, and maintain some distance between each other. That way, the mask keeps the virus relatively contained to yourself, while providing some minimal barrier of protection from others.
The reason why the CDC does not recommend this, is because of the mask shortage. They want to keep enough available to the health care workers. Which I understand, but if the public also uses a mask, then it would also minimize or slow down the infection rate.
If you are working in public, or even if you are doing grocery shopping for yourself, then I highly advise to protect yourself, to take this issue seriously, and wear a mask.