It didn't occur to me like this until now ( I was too upset about the pick trade) but if Danny really did get his man at three that he would've taken at one then the draft would've went like this without the trade:
#1 Tatum
#2 Ball
#3 Fultz
#4 Jackson
So not only did Danny get his man and pick up a good asset, Danny also got a team to give up an asset for a player that they would've gotten anyway. If the Sixers knew, and they should've, that The Lakers were taking Ball at 2, everybody knew this, then the sixers would have to know that the Celtics didn't want Fultz at one ( as they were trading the pick) and that he'd have to fall to the Sixers. The Sixers not seeing that and Danny seeing it is why he's sure a good GM! Chess instead of Checkers...