they are looking for content, BYU and the Sun Belt both provide cheap content. With BYU they get a solid team, they can air, and because it is not part of a conference, they do not have to choose games like they did with the Pac-12, Big 12, etc... If ESON had to choose between USC and BYU or Texas and BYU, you would see a lot less of BYU on TV. This way ESPN does not have to choose, and my prediction is, even when BYU has a down year, ESPN will maximize the amount of games shown. They own the content, and it does not cost them any rights to air it.

Almost any mid level BCS team could get an equal or better contract from ESPN.