to help fund their program by playing a one-off game on the home court of the D1 goliath team. If the D1 goliath team has money from season tickets or other sources, they will have the money to pay for all of these buy game costs. Perhaps the fans are happy because it means more home games.
and as a caveat - our preseason is just 1 game long. it seems like you are referring to the non-conference portion of the schedule. The non-conference schedule are important games that count towards your tournament profile just like the conference games do. The conference games are only more important to the extent that it helps towards getting the automatic bid from your NCAA tournament. But for BYU now in the modern era that auto bid is pretty irrelevant. In a 16 team conference it will be rare even for the good teams to get the auto bid, just due to sheer numbers. BYU will usually get into the tournament via an at-large bid.