Veteran players who are playing well get bought out every year.
The season is about 2/3s over so the Jazz would be buying out 1/3 of Westbrooks contract, or $15M. So Ryan is basically buying 2 incredibly valuable trade chips for $15M, that he would have been spending anyway. The Jazz just don’t get the services of the players moved in the deal.
Westbrook can then go sign with whoever he wants for the minimum. He’s happy he doesn’t have to come to Utah, and the Jazz are happy to not have him so their young players continue to get more time.