The edge he is referring to is financial. Since Jackson comes completely off the books next year, that would allow ATL to maximize their cap space. A player like Humphries, which is still owed 12M next year, eats into their ability to chase max-level free agents.
I think ATL knows they are not going to get a top flight talent for a guy like Smith. Their goal is to get some assets while opening up as much cap space as possible it appears. That could change and someone might offer them a great player, but unless it's a player they love, they would likely rather have cap space, draft picks and maybe a good young player on a cheap contract instead of a better overall player since their eyes are on free ageny. Hence the "edge".