Arizona's reported interest in San Francisco quarterback Alex Smith could help the 49ers more than it helps the Cardinals.Think of it this way: The 49ers aren't going to trade a starting-caliber quarterback to a division rival, but if a division rival shows interest in Smith, that could help San Francisco leverage better trade terms from another team.The 49ers are seeking to trade Smith to avoid guaranteeing $8.5 million to him in 2013. Trading Smith would beat releasing him for reasons beyond trade compensation.