In the context of cryptocurrencies, the tokens themselves have value and they can be audited thanks to blockchain technology. Before blockchain, it was not possible to verify that the supply of a currency had not been tampered with. This is why the US was forced to abandon the gold standard in 1971; it turned out that more dollars had been issued than there was gold to back it (gold is difficult to audit because very few entities have access to it and this makes room for corruption). If the dollars had been backed by a cryptocurrency instead of gold, this may not have happened. We would not have been forced into a soft-money standard.