Denver gets to keep playing a high-post playmaking style even when Jokic is off the floor with Plumlee. Being able to run your offense consistently across the first and second units is good.
Portland gets a center who's (theoretically) a better rim protector and doesn't have to pay Plumlee a billion dollars in the summer anymore.
Kind of puzzled how Portland ended up upgrading a 2nd to a 1st in the process, but I suppose Denver just wanted the trade more. Makes sense both ways.