Is to always make sure the Big 12 Is regarded as competitive enough to merit the first round bye in the next round of negotiations.
Since we already have the berth this year, I think you are correct, Winning the conferences far more important than ranking.
Where ranking might matter is beating out the ACC for the #3 seed and potentially getting in a 2nd berth.
For all those reasons, I think the majority of Big 12 fans will root for the higher ranked teams to do well… Especially when it comes to out of conference games or playing lower tier B12.