Steve, if you search for "studies on wearing masks to prevent covid-19 transmission", you'll find loads of information. I'd post links, but I think you're smart enough to do your own research.

In any case, preventing Covid-19 infection may not be as important to you as it is to people in the US, since we've got rates of infection through the roof. Even so, it's worse in some states than others. I suppose if you don't have to worry about accidentally killing someone, you don't have to think about wearing a mask.