CV was traded because Colangelo recognized that he was going to be overvalued coming off a solid rookie season.
He wasn't as good as his rookie numbers indicated, and showed less growth potential than most due to the lack of motivation and the laziness previously discussed. Plus he played an already strong position.
So BC flipped him when his value was the highest for a position of need. Simple as that. He would've made the same move regardless of who the draft pick was going to be, given that there were no can't miss point guards in that class.