There aren't many elements on the periodic table, and even fewer are viable as metallic currencies: rare enough to have value in small weight, not so rare as to be foreign (historically) to many cultures. Gold has a visceral, visual advantage, too: it's the only yellow metal.
On the other hand, anyone can launch a new cryptocurrency. There's no natural monopoly there. The idea is valid, but all Bitcoin has to defend itself against competition is the brand/reputation. And people hate Bitcoin because it was clearly set up to favor early adopters for no good reason.