I think bitcoin is the first truly global currency and it truly does have the power to be a borderless, worldwide currency. My dream is that it just catches on so everybody else sees it like this because without being able to spend it at many places across the world it is kinda useless as a currency but I think this will change over time.
Gold was (and still remains) the first true and truly global currency by any means and thus for hundreds of years already. Whether bitcoin will be able to make it like gold did, remains to be seen. Personally, I think bitcoin is currently stuck between fiat and more apt cryptocoins, so it is not given that it won't be supplanted by them eventually...
Gold isn't very good as a currency for many reasons. Bitcoin is far superior in this regard in almost every imaginable way, though gold obviously has intrinsic value as a precious metal.