They aren't buttons, it's a touch screen. Meaning: fuck blind people and touch typists.
Edit: at least there is an option to get actual function keys in the 13" model if they are required to use Voice Over and they cannot be reliable found on the touch bar... and the user won't really care about the screen size (I'm joking, I can think of many reasons why a blind person might want/need to use the 15" model).