By what leap of logic do you assume that they would have recognized a gold or silver coin? Most Americans have zero experience with either, and we have much more access to both. That is the problem with PM during TEOTWAWKI, it will take time before even PM are recognized for what they are. This is why barter items are better for that. Just about any event less than TEOTWAWKI, and the Internet will still exist, and so will Bitcoin.