We need to spend the money somewhere.
Let me put it another way: in any given year, teams have a salary floor that is a certain percentage of the cap (I've read between 85-90% depending on the source).
After the signing of our draft picks and the cap holds for our RFA's, we are actually not too far away from the floor. Depending on how a potential howard trade is structured, we probably won't take on that much extra salary, so that's not a huge deal. What is a potential problem is next year.
We have 22 million in guaranteed money, about 7.5 more for QO's for hendo and mullens (if we extend them), about 6 more in options for kemba and Bismack, plus up to 7 more for cap holds for Carroll and williams (if we don't renounce their rights... I went ahead and assumed we weren't going to accept the 8+ million cap hold for diop's contract). That's putting us at about 7-10 million below the salary floor.
So her me out- we have to spend the money anyways. If picking up Ben Gordon and Kris Humphries means adding a few first round picks or Marshon Brooks or getting at least a marginal veteran presence on the team (something that was sorely absent for every game that maggette was injured)- we have to spend the money anyways. Why not add a few picks while we are at it?
Side bar: Assuming we're aiming for the salary floor, this is why amnestying TT is not a good idea. Keep in mind that amnestied players still count towards the salary floor, but if we are not gaining any benefit financially (IE we're not signing max free agents), there is no purpose in cutting him.