Why the Warriors do it - They get a haul for giving up the #2 and 2021 Minnesota Pick. First they get to offload Wiggins who's contract is horrendous. Then they get back the #7, Rose, Kennard, and Gibson who could all be valuable championship roleplayers.

Why the Pistons do it - The Pistons are likely heading for another rebuild as Griffin hasn't been the star they needed. The #2 pick is potential star power in Ball, Edwards, or Wiseman. They are able to offload a horrendous contract in Griffin. They give up a lot of assets, but they are getting a bunch of cap space and the #2 pick.

Why the Knicks do it - The Knicks have already said they would take on bad contracts for Assets and this is exactly that. They take a gamble on Wiggins and Griffin who have monstrous deals, but are potential all stars. They pick up Paschall, Dembouya, and potential early 1sts for their troubles.