Masks seem to have some effect limiting the spread of Covid-19. Even if their efficacy is overblown that shouldn’t be a reason not to use them. They’re something easy and low cost we can do, and they’re one of the few things within our own control besides staying completely isolated.
U.S. airlines now require masks. And Marriott has become the first to announce a mask requirement for all guests in on-property indoor spaces and not just for employees. This requirement goes into effect July 27. I expect the other major chains will follow.