This feels like positioning to me.
BYU wants to be the "ND of the west"? Why? We don't rake in the money from NBC that people always seem to think we do. No, its more because of the power we have. When the superconference thing happens (its only a matter of when now, not if) ND is basically calling the shots. The Big East and/or ACC may go under completely based on what ND decides to do. The Big Ten beckons, and no matter what anyone says about Texas, ND is the entity in control of what happens.
BYU wants to be in that position in the west. When the superconference dominoes start falling 6 or 8 years from now, they want to be able to go wherever they please without any other messy affiliations to have to deal with. They are in a unique enough position to be able to pull it off.
Good for them, I say, but this isn't a permanent move, nor is it some kind of statement about the value of independence in college football - its just a move to put themselves in position for the next big shift.