ND obviously carries more cachet than BYU, but go look at BYU's schedules as an independent for the next few years. In 2019, they play Utah, Tennessee, USC, Toledo, and Washington in August and September, and in 2020 for the same months, Utah, Michigan State, Arizona State, and Minnesota. In the other months, it's USF, Boise State, Utah State, Liberty, Idaho State, Umass, San Diego State, Missouri, Houston, Northern Illinois, North Alabama, and Stanford (on the road).
The conference arrangement allows us a more balanced schedule with teams like Miami, Florida State, Virginia Tech, and Clemson obligated to travel to South Bend in late October and November which would never happen as an independent. Teams in major conferences generally don't want to travel for a "meaningless" non-conference game late in the year to South Bend or anywhere else. Michigan only agreed to the game this year in late October because we allowed them to use B10 refs at the Big House instead of ACC officials.
The ACC deal isn't ideal (5 games a bit too much for me), but it was a good move by Swarbrick.