The Heat, starved of draft capital, get a few valuable picks, for taking on Simmons and Williams expiring contracts. Those picks and that cap flexibility will make them a premiere destination for free agents next summer.
Beal would have to agree to go to a rebuilding Nets team. But they're in play for the #1 pick, and can make additional moves down the road. Plus he'd go back to being the #1 option, instead of coming off the bench.
Phoenix gets Jimmy.