I'm not really sure what the laws are on "paper" gold and other precious metals. Do financial institutions that sell precious metal investments have to have the physical metals to back everything they sell? A certain fraction? It probably varies by country...

Regardless, to the extent that I invest in precious metals (which isn't a whole lot) I get the real thing. As far as cryptocurrencies are concerned (and don't get me wrong, I am a huge supporter) I think a lot of the value you see today is based more on speculation than anything. I don't think there is yet a good way to judge the long term potential for a given cryptocurrency. The things that make physical precious metals go up and down in value are pretty well understood and relatively predictable.