There was huge hype around Mariah before TMB dropped because of TEOM but TMB is a great pop song and it was a great single at that time. It's one of the best songs on the album.
Obsessed had a lot of hype around it because of the Eminem drama but after all the flops on E=MC2, Obsessed could have easily tanked so it was a great single and perfect for her career at the moment.
So The Dream might not be everyone's favorite person after Memoirs but he does deserve credit for being involved in her last two big hits.