It's not immediately obvious from the label what the button does, but it is from experimentation. And unlike the multistep 'cut' or 'paste' buttons or 'move to'

It's not immediately obvious from the label what the button does, but it is from experimentation. And unlike the multistep 'cut' or 'paste' buttons or 'move to' (which pops up a dialog, I think?), the discovery process for a user is one click. Or maybe two. One to go from selected file to all other files, and another click to get back.