A crypto doesn't need to be backed by gold. In fact, that would be redundant, as both gold and crypto serve exactly the same purpose. They are merely accounting mechanisms to facilitate trade in real wealth...i.e. necessary goods and services.

They both derive their utility in this function (which establishes their value) by the fact they can not be created infinitely out of nothing. Neither gold nor Bitcoin really have intrinsic value. It what they can be traded for which gives them value, which includes the perception people have that they will continue to perform that function in the future.

Anyone who is smart will hedge their bets on both types of currency. Public blockchain, limited, mined cryptos such as Bitcoin, and gold back currencies.

(Note that PoS cryptos (proof of stake) and CBDC's like Ripple don't have the required legitimacy to be used as money. They are like fiat currencies, which can ultimately be controlled by a small group and lose that legitimacy of being a trustworthy medium of trade and storing value.)