Yes, it has failed as a currency, and later as an asset backing up a currency. The said doesn't mean that its price dropped as it actually has increased over time with the dollar constantly depreciating. Gold surely didn't fail as a store of value. Personally, I would go for a tighter definition of currency that assigns more significance to it as a means of exchange before anything else...
Well, if that's failure, then hopefully Bitcoin will fail.
That said, Bitcoin has a number of advantages over gold when it comes to exchange. It's much more easily divisible, down to a fraction of a penny currently and is theoretically divisible even more should one satoshi become worth more than the current value of one penny. It's much harder to counterfeit (nearly impossible unless SHA256d is seriously broken), and it's much easier to check as valid (anyone can do so on a computer with Internet access as opposed to the techniques needed to prove that your gold bar isn't filled with tungsten). And, of course, as I discussed previously, you can irrevocably transfer it over the Internet in a way which can't be double-spent.
The gold now is neither currency nor an asset behind it, so enumerating Bitcoin advantages over gold as a means of exchange sounds really strange these days. Everything would change if you tried to compare Bitcoin against some well-developed fiat currency (say, dollar) or against gold as a store of value...