That would definitely help us for several reasons:
1) They can't sign both Durant AND Conley, so signing Conley would mean Durant is no longer an option for the Spurs. Hell, they're going to have to do some serious cap management to just sign one of them.
2) Signing Conley would once again make them a very, very deadly threat in the West, even after this horrible showing in the playoffs. That could definitely be another deciding factor in Durant heading East. Their defense would be EVEN SCARIER if they started Conley alongside Green, and their bench would be bolstered by Parker's presence.
3) Conley leaving would also make it much more likely that the Grizzlies would trade Gasol, who in turn is probably much more attractive to someone like Durant than a Boogie or a younger player.
I can't really say how it affects the pick we get from them, but that's a long ways off anyways. Conley going to the Spurs is nothing but excellent from our perspective.