The supposed magic of playing an FCS team early in the season is to have a relatively non-threatening (ok, cupcake) full contact scrimmage sort of like an NFL preseason game, where the FBS team can get some reps in for the first team, leverage the imbalance to provide playing time and meaningful snaps in for the backups. The FCS team gets a good infusion of cash from any broadcast time, and it also can get some remuneration from the gate. This is usually a pretty nice setup for both teams, and the FCS team can get some bragging rights if they do well.