Gold has had its reputation for centuries. Simply, there is nothing that can compare in that respect, and it is really hard that it ends up being worth nothing after centuries of being a valuable metal.
Indeed, and I also think its a primary currency, think about the fact when everything will collapse the gold will still be standing and we will pay with it for sure if every currency will collapse I'm pretty sure about that.
Gold is just the most important currency in the world in my opinion, I think if the bitcoin fails the gold is the best currency to invest in in my eyes, there is just so much profit you can make with gold on a long term.