If you are looking for convincing evidence in favour of mask wearing - this paper is not it.
It bases its conclusion on a few hundred cases in the German city of Jena back in April. In fact, the authors themselves apply the same analysis to other cities over the same time period (figure S15 in the supplementary material) and those plots show hardly any effect.
However... if a paper claims to support X and the paper is bad, then that does not mean that X is incorrect. And given government advice around the world, it seems pretty clear that masks are understood to do more good than harm.
It bases its conclusion on a few hundred cases in the German city of Jena back in April. In fact, the authors themselves apply the same analysis to other cities over the same time period (figure S15 in the supplementary material) and those plots show hardly any effect.
However... if a paper claims to support X and the paper is bad, then that does not mean that X is incorrect. And given government advice around the world, it seems pretty clear that masks are understood to do more good than harm.