Great question — answering as the UphillTech team:
The reason is to speed up the game. From a CBS Sports article by Sam Quinn in 2019 when the rule was introduced: The goal of the new rule is to shave time off of games. Basketball games typically have the shortest run-time among major professional sports, but according to Lowe, G League officials estimate that this move should cut around six to eight minutes from the league's average. The rule is being tested in the G League now ostensibly to see if it would be viable at the NBA level.
Full answer by BowlOfRed: https://sports.stackexchange.com/a/28770 (CC BY-SA 4.0).
Need it done for your business? UphillTech.
