I think you need to read that again, It says nothing about needing a DX11 card to use the textures, but probably that they look best when used with the other DX11 stuff.
Its also not just about adding features, its about performance too. Even today, FEAR has a huge hit when you turn soft shadows on (game is still playable, but imagine that kind of hit when you arent runnning at 150FPS+) and they don't even look that great.
DirectX 11 won't make your soft shadows magically way faster, it's all marketing gibberish. The fact that almost every single PC gamer buys into it almost instantly is what bugs me, I didn't think the community was that naive.
Most of these DirectX11 games just make the DX9 and 10 versions uglier than they could be to make the DX11 version look better by comparison. Crytek did it with the original Crysis by blocking out the very high settings if you didn't have DX10, meanwhile if you enabled those settings in DX9 mode, it ran every one of them better, at the same visual quality.
Just look at the DX9 version of DAII, the textures are lower resolution for no reason, they don't appear to even have bump mapping, they certainly don't have POM's, and the shadows look on par or worse than Nocturne from over 11 years ago, which runs on DirectX7.
Even if there was validity to meaningful performance gains under DX11, the fact that they purposely gimp the DX9 and 10 versions is reason enough for me to dislike them.