Because basketball IQ, or smart players, are really important. They make less mistakes, understand situations and help a team perform at a higher level.
Blake Hoffarber has a high basketball IQ. Chris Webber did not (in college at least) and it showed and hurt his team.
Just because he wasn't highly touted doesn't mean he can't be great. When kids are 16, 17 or 18 there is a good chance they will improve, grow or get a different body. If Walker gets a more mature body and continues to grow as a player, he could be very very good. He has great footwork, soft hands, finishes around the hoop, can hit a jump shot (something Iverson and Mbakwe cant do) and he is a a huge person. All of those things, plus his basketball IQ, make him a potentially great player.