The flow resistance of the mask greatly limits the spread of viruses in the room. This significantly reduces the risk of infection in the vicinity of an infected person (protection of third parties).
Surgical masks are effective for bacteria (a large concern in hospitals) not viruses. This is precisely why they have never been recommended for flu like viruses. This study you cited is the type of scientifically poor study the University of Minnesota talked about.
I guess surgeons don't have to wear masks when doing surgery then.
On a more serious note, masks stop droplets. It stops people sneeze and cough emitted droplets from being expelled.
https://www.sciencedirect.com/science/article/pii/S0021850220301063
Surgical masks are effective for bacteria (a large concern in hospitals) not viruses. This is precisely why they have never been recommended for flu like viruses. This study you cited is the type of scientifically poor study the University of Minnesota talked about.
https://www.cidrap.umn.edu/news-perspective/2020/04/commentary-masks-all-covid-19-not-based-sound-data