I think that that even if Sheraton is not the synonym of Four Seasons nowadays, it's still Sheraton and people associate the name to a well known/upscale brand. To some...most people you could say Sheraton or Marriott and it would ring a bell. I don't think that mentioning 4Points or Courtyard would necessarily do the same; hence by Sheraton, by Marriott. That's my view on the subject.