^^ To me it seems that with a fat bike build having high end (light ) components would be crucial.
The bike you posted is steel with low end wheels it looks like.. Imagine it an all carbon (frame, rims, post, bars, stem, seat) decked out in xx1... Would be an entirely different beast I'd assume. I also think the tire manufacturers are going to be coming out with some fat tires that can affect the ride drastically with their weight and performance. Cross country/weight weenie fat bike.. it's coming.
That's why I've been somewhat put off by fat bikes thus far.. They just look and seem sluggish. But seeing that all carbon one above, made me reconsider the possibilities. Either way, it's definitely something I'd ride first before buying as I realize that what you said could turn out to be completely accurate and therefore make it more of a "novelty" bike.. Which I have no interest in.
Gotta get myself a test ride in on one decked out in all carbon and top end components.