I've always thought bowl games were interesting and important for one simple reason. Teams mostly play an 8-9 game conference schedule, with a few non-conference games at the beginning of the season. How do you compare teams from one conference with teams from another conference? The only comparison is when you have games between them. The early games give you some comparison of where the teams were at the start of the season, but the matchups are often bad. If the first place team in the MAC beats the last place team in the Sunbelt in an OOC game, you don't learn much, and similarly you don't learn much from a game between the last place team in the MAC against the first place team in the Sunbelt.
By contrast, bowl games are going to be games between the top few teams in the MAC against the top few teams in the Sunbelt, and then you finally get a direct comparison. Similarly, you get some comparison to CUSA, MWC, and the AAC, and occasionally, against a P5 team.
So, what games were there between the MAC and the SunBelt this year? For two relatively equal conferences, there were remarkably few games between them. In fact, I can only find one regular season game, where WMU beat Georgia State 34-15. Add in two bowls, with Buffalo losing to Troy 42-32 and EMU losing to Georgia Southern, 23-21, and those are the only basis for direct comparison between the conferences.
So, has the SunBelt passed the MAC? With only 3 games to answer that question, I'd say that we don't have enough information to answer that, but it would have looked better if the MAC had won at least one of the bowls.
“We have two ears and one mouth so that we can listen twice as much as we speak.” ― Epictetus