Of course you are right about Gold, it's valuable mostly because it is popular and we've agreed that it is valuable - for a while, aluminum was more valuable than gold, because it is shiny and was scarce. You could argue that aluminum is actually more "useful" than gold. Most things are either valuable because they are scarce (mainstream economics) or because a lot of labor went into it's production (labor theory of value/Marx). But things that are not money seem to need a "practical" use to be able to hold value.

Interesting fact about gold, for a while private gold possession was banned in the US. So even in that regard it is not a to Bitcoin...