It's totally crazy arguing that the don't. Most normal hospital use has always been mostly to prevent the people who do the work from infecting patients. It even goes way way back in history. Covid in this respect is no different to other infections.Yes, it does. Studies show that masks reduce the number of cases of community transmission.
They are not so good at protecting the wearer from infection but much better than things such as doctors used to use that caused them to be called quacks or nice smelling things etc because it was the smells that caused the infection.