The Mavs get their 3&D they desperately know they need. Dallas sheds a bunch of unwanted/unneeded debt for players not producing towards winning a title. This gives the Mavs more options in the off-season, as well.

The Spurs shave older players and a young unproducing debt that did not work out as planned.

The Warriors shed even more debt than retaining CP3 just to decline his team option. Including Thompson's contract off the books, the Warriors shed approximately $84M in contracts for next season. The Warriors retain the rest of their winning core, re-sign Saric for more, and maybe re-sign Klay to much, much less. If Klay walks, the Warriors have room to spare for additions under the 2nd apron.