I'd be more worried about the fact that BFG went bankrupt last year and you have no warranty if anything goes wrong than whether or not it does DX11....but thats still a good card as long as it works.
On a side note Yes DX11 ready, and somewhat ticked if they don't put it in. About 2 months ago I went From a radeon 5870 and Phenom II 95 at 3.8ghz to my current I7 875k at 4.0ghz with Hyperthreading and a GTX 580 cause i thought the extra power would be needed for this game. Not really a waste cause my son now has my old (not really old) processor and graphics card, so yep im ready, hell my son is too and he will never play this game probably for another few years (only 9 at the moment not into shooters yet).
And the question is sorta like asking people who never use premium gas do they need it, of course they are going to say no, however there are people who do use it and it doesn't take anything away from the people who don't so why does it really matter.