Many leagues and clubs require teams to supply a certain number of referees to their home games. In order to track this, referees "Affiliate" with a team so that the games they referee can be credited to that team.
Every game a referee refs generates a credit that they can then give to a team. The credits are apportioned by the system automatically to the teams a referee is affiliated with, up to the amount required for each team.
After that, the referee can assign their credits to any team and can even sell them to teams that need them.