I think it's obvious that running the half-court offense through Josh Smith in the mid- to high-post improves both Atlanta's spacing and floor balance. It was not immediately obvious to me but now seems clear that a contributing factor to this is that Josh Smith's defender is going to close out on Josh Smith whether he's likely to attempt (much less make) a jump shot 15+ feet from the basket or not.
Frontcourt defenders posses a tremendously strong instinct (probably instilled) to close out to that spot. Most of the guys who will be defending Josh Smith in that position are susceptible to Smith driving past them. Due to the illegal defense rules, however, they can't play off Smith below 15 feet. When Smith catches the ball in that position, his defender will, most times, be moving toward Smith just as Smith wishes to move past him to the basket or use the space in the lane his defender is vacating to find a cutting teammate.
And, even if Smith's defender possesses the quickness and balance to close out without leaving himself vulnerable, a simple shot fake, no matter how improbable said shot being made is, could also improve Smith's opportunity to get to the basket or find an open teammate at the basket. Case in point: Anderson Varejao. In 1863 minutes this season, Varejao has attempted 78 shots outside of 10 feet. That's one jump shot every 24 minutes he's on the court. He's made just 29.5% of those shots. Yet his defining offensive move* is the pump fake and dribble drive and it's a relatively effective one. In the hands of Josh Smith, it could be devastating.
*discounting the uncalled illegal screen