Lets see:
We could have had these picks: 1,1,2,3,3,4, and traded our 4th, leaving us with: 1,1,2,3,3.
Instead we take their 4th and trade it, leaving us: 1,1,2,3,4. Sure makes sense to me. Why would we want a 3rd rounder when we could have a 4th instead. Oh, i know, we got an extra 6th round pick. SUPERBOWL BABY!!!!!