The ACC gets 2 to 3 home games with ND every year, which is a negotiating tool to bump the ACC TV rights contract payday. That is the really the only benefit. It's something, but not a lot. Also, last year, ND was in the ACC and so the ACC had two teams qualify for the CFP, which ND had to share. IIRC, the highest rated CFB game of 2020 was Clemson at ND. Again, it's something, but not a lot. Would guess the feeling at the time was that by reaching an agreement with the ACC, it was a step to full-time membership, which would benefit the ACC. A decade later, ND is no closer to joining the ACC. So, there benefit of adding ND (kind of), its more than nothing, but not a lot.