Reading the stats this morning the current death rate is below the average for the time of year. Why are we wearing masks?
Because recently the gov have advised/allowed that social distancing is lessened. Remember supermarkets with one way systems, only so many at a time, etc . No shops open (except food), etc
Now that we are nearer each other (for some little time), it is of benefit, to keep the R rate down , to wear masks. Some argue otherwise, but generally they prevent less breathing of each other's expelled breath.
"Every little helps"😀
And, of course, it is one of those situations where you cannot quantify how much they help, ( I.e prevented infection) , but that doesn't mean they do not.