Well, I think in a way it would infringe on a benefit of BTC, but regardless of what you do with Fiat, its still... well fiat... You can take a piece of crap and put a dress on it, and hit it with some Febreeze but its still a piece of crap. I think people will continue extolling BTC 's success or failure based on its 'fiat' value. But as more and more services come online that can help you full-fill your needs with BTC it won't matter.
Look at Dwolla, its offered $.25 transactions of cash up to $5k usd anywhere anytime in the US. I thought it was 'amazing' years ago when I heard about it. I jumped in because it was basically almost free to send cash. I think dwolla has done well, but I almost feel like its obsolete now in the face of bitcoin (thought they are very different) because it is truly different. If all people cared about was moving dollars around cheap Dwolla would be huge, But its niche at best.
Bitcoin is a whole new way to get it done, Fiat be damned.
+1