They picked Nolan Smith for the same reason the selection committe gave Duke a #1 seed, because they are DUKE.
SDSU deserved that #1 seed more than Duke, they had a better record in a conference with a better RPI. Their only losses were to a top 10 team with the best player in the country.
Not that i have any love the Aztecs, i'm just sayin, this year Duke gets the hook up based on repuatation alone and not on merit.