Apparently, there's a critical mass of SEC teams who will only vote to go to a 9-game schedule if they can play their three OOC games against The Citadel, College of Charleston, and Mercer.
I think I remember over the last decade hearing much prognosticating about how the expanded CFP would encourage teams to play tougher OOC schedules. Now, at least with the SEC, it appears that all of that was hogwash. Just another set of lies to sell the expanded playoff.