I'd be sceptical about the long-term future of such standalone cards - this functionality seems more appropriate as part of a "game card" (graphics + physics) and I can understand both Nvidia and ATI making noises about adding it to their cards (an opportunity for Nvidia to plug Quad-SLI also) though using a full GPU for it isn't a great choice to push on gamers.
In addition, while previous add-in cards provided an upgrade path for gamers (e.g. the original Voodoo which allowed you to use older systems with the newest games), this seems to do the reverse - giving games the ability to place higher demands on the CPU/GPU. As such, I'd expect it to go with way of the ReelMagic (an add-in card that provided MPEG decompression for full motion video in games) - being incorporated into other products as a tickbox feature.