Well unless the fps hit is 5 or less, then it still won't be worth it. Tessellation & PhysX wield infinitely better results aesthetically and give nowhere near the relative fps hits for what they actually do. This just seems incredibly contrived and gimmicky, almost completely arbitrary on AMD's behalf which isn't exactly their usual M.O. I can see it leading to better things in the future but the way it behaves now feels as though it shouldn't of been implemented into any game yet and AMD should have worked more on optimizing it. I really hope they aren't so big headed that they believe anyone will want the fps hit, just for better hair on a single character.
With the exception of Borderlands 2, PhysX doesn't hit a games frame rate nearly as much as TressFX has, but which is better? The results that TressFX has yielded to me looks like something that PhysX could have done for nowhere near the same fps hit anyway, as it just adds better behaviour and sharpness to a single instance of hair. This kind of fps hit would be understandable if it also applied to animals, fabric, all NPC's and even foliage, but as it stands the performance hit is baffling.
If this does evolve from a gimmick and actually becomes a worthwhile tech, I do hope AMD at least offer it to Nvidia, as Nvidia did offer them PhysX even if they refused it.