I really liked Avery as a player, and he seems to be a quality person and teammate. Really fun watching him develop. I wish him well, and I'm sad to see him go.
That said, I like the trade for the financial reasons a lot of others have mentioned. Another thought - this team has really benefited by finding low cost players and getting more out of them than others did. Given what the Cs have done with Steez, Evan Turner, Gerald, Jae, and IT, I have some hope for Marcus Morris being able to contribute as a rotation player.
But I really hope our rotation of bigs is going to improve before the playoffs. The one reservation I have about this trade is that it rules out the trade I really was hoping for. Something like Jae and AB for a big who was worth a 12-13 million salary. Someone like JaMychal Green. But I have no idea if that trade was out there, so it's hard to hold it against DA.