D-Wade being back is pretty awesome. Getting Babbitt back for next to nothing was a solid move too.
The benefit here for the Heat is obvious. They make a massive and necessary roster shakeup without giving up on Pat Riley's desire to win right now. Towns being coached by Erik Spoelstra can only be good, but he also allows Miami to be more modern. Whiteside, a traditional big, has been an awkward fit for so long that having someone like Towns, who can stand on the perimeter, will be good for Miami.
By moving Dragic, the Heat will also be able to use Towns as more of a creator than he was in Minnesota. They'll still have Jeff Teague and maybe Dwyane Wade, but Towns should definitely have the ball in his hands more often in Miami. At worst, the Heat get a star big man on the roster and clear out some players that have been an awkward fit for a long time.