But you said it yourself (more or less), the best team doesn't always win, advanced metrics help to quantify "the eye test," talent composition, performance vs. the strength of your opponent, etc.
NIU beat us last year, were they better than us?
Head to head is a factor, but it's never, ever (and I mean, EVER), been the end all, be all in CFB. We have to decide if the CFP is tasked with getting the best teams in, the most "deserving" teams, or if it's just an invitational to enrich one network and the conferences that it owns (hint: it's the last one).
As to the "why even play the games" talking point that was hammered on a loop by Miami media people and ESPN, if an entire season can be boiled down to a single game, why even play the rest of them? The season is 12 games long. Performance can vary for a number of factors from game to game (such as the reasons we struggled the first two games), but advanced analytics can help to gauge the consistency of performance throughout a season. There's a reason every computer model, every single one, had us ranked higher than Miami, generally by several positions.