This is also the stance of the article. Whether masks protect the person wearing them is still very important, firstly for the protection itself, but secondly

This is also the stance of the article. Whether masks protect the person wearing them is still very important, firstly for the protection itself, but secondly because some people are motivated more by self-interest than altruism. If you tell everyone that masks don't stop you getting sick, when in the balance of probability they do prevent some cases, then fewer people will wear them.