Mark Cuban disagrees. We still hear complaints about the rookies coming in unprepared, projects who will take 2-3 years before they can truly contribute. A NBA team could stash that project on their own Developmental team, like a AAA Minor league baseball team, let that kid work on his game and get called up when he's ready. This will help teams like the Wizards, who developed Seraphin on their NBA roster, wasting years on his contract, while someone else is likely going to reap the rewards.
It also could help NBA older veterans stay on a NBA roster, or give them a place to finish out their career instead of retiring when they aren't prepared mentally or financially. That would also lead to better basketball with higher BB IQs on the court.