Getting in with the B12 leftovers would, probably:
Get us a better media contract. The non P4 contract money is never going to be the same as the big boys, but the ex-B12 conference is probably going to have the best one.
More name recognition against opponents. There is no doubt that games against teams like SMU and UH still draw more recognition from the local fans, even though the SWC died almost 25 years ago.
Who has brought the most visiting fans? Teams like Baylor and Houston. Wouldn't it be nice to play them every year?
Water cooler talk. It hard to get pumped up playing FIU or MTSU when you've never even met a single person who went there. But how many of us could trash talk Tech or UH co-workers/neighbors/family. That creates buy in.
So, if you the only "benefit" you see is "getting into a P5/P4 conference." Then no, I don't see any path for us. But just like CUSA is a better for us than the SBC, which was a better conference for us than the Big West, being a part of the ex-B12 conference would be another step up.