Indeed but there is no evidence of any decrease in the R value
Masks have been mandated in many countries, each with its own different factors, but there is no evidence of any correlation between mask mandates and decreasing cases.
Indeed, however there's also no evidence that it doesn't (except in very high risk settings where it may have a small increase/decrease).
As where it could have a limited impact the exposure time would be limited and so the difference is only ever going to be small.
Other things (like washing hands, limiting exposure time and most of all the vaccine) will have much larger impacts.
It was worth trying face masks, and for those in high risk settings and at high risk to wear proper masks, however now it's not.