The Big12 problem isn't that they can't make the CFP. It is that they have to show they are clearly better than a team that wins its CCG.

The Big12 will comeout ahead, occasionally, when a CCG-winner upsets another team that was more likely to get in. But I think they mis-calculate how often a CCG-game will include a team unworthy of a CFP spot, and how often that un-worthy team will win. It will be rare.