It's nice... but I can't see a lot of sense in this. First, there already is Nvidias FXAA, which runs well on both 360 and PS3. And second of all, because of the eDRAM the 360 has more or less free 4xMSAA, which should be enough for most cases anyways. Well, you engine has to be able to tile the framebuffer and you can't use deferred rendering.
Still, it's always nice to have the option.