The "only" game? Are you saying that there's only one game in the entire gaming market that supports Physix cards? I doubt that.

Well, there
may be some other games currently in developpment that would support those cards, but I highly doubt it.
The fact is that when you develop a game, the physic engine is really a big part of it. If you choose to use those cards, then that means that you won't implement a physic engine and rely on those cards, but what if a player doesn't have this kind of card ? Is there some equivalent to the DirectX software graphic mode ? Then how poor would be the performance in that case ?
I think that most of the developpers prefer to keep full control on their physic engine, the way it is implemented, the way it interact with the rest of the program, the way it works. I am pretty pessimistic on this PhysX stuff to be honnest.