Well, it could target the situation of teams making late acquisitions just to bolster up their Playoff Squad.
In addition, since BB is not using the NBA trading system but a "transfer fee" system (where you basically pay the original owner for erasing the contract), it´s only realistic, that players demand a new contract when signing with the new team.
In a system like that, you could add a discount when beeing with the team for 1, 3, 5 seasons (like 5, 10, 20%) to make "homegrown" players more valuable for their teams.
Zwei Dinge sind unendlich, die Dummheit und das All...