Why the Suns do it: They lost to the Bucks in the championship, and they bolster their bench by getting someone that can play good defense and can provide good veteran leadership. An already top 10 defense in the league in terms of points allowed gets even better.
Why the Spurs do it: They get more assets for the future, including a former top 10 draft pick, and he can get more of an opportunity playing on a rebuilding team. Plus they get 2 seconds, which is pretty good value for an expiring deal