Here's the way I see it:
When I go to on-campus college football games... it's unequivocally different than attending a game in an NFL stadium miles from the school. I want an OCS to get that college football feel at MY school, not someone else's. I want to tailgate at USF, not in a dale mabry parking lot.
Beyond my own interests.... I have to imagine that an OCS makes a profound impact on student life. Walking to the stadium is a lot different than driving, bussing, whatever... it becomes a center piece of the university. Additionally, I DO think it's relevant to future P5 consideration. UCF has one and we don't... the differences in our universities are relatively small and we should address any area that makes UCF a more attractive option.
Yes, it's a ton of money... but it's a long term investment in athletics, student life and the university as a whole.