According to Zach Weinersmith, author of Soonish, the only argument I’ve heard about cryptocurrencies is that it makes sense within the framework of believers themselves, who don’t want a centralized currency issuer.
But within this framework, why not just use gold? To this, Ethereum co-founder Vitalik Buterin replied that gold is very inconvenient, it is difficult to use, especially when transacting with untrusted parties, and it does not support secure storage options such as multi-signature. At this point, the adoption rate of gold is lower than that of cryptocurrencies, so cryptocurrencies are the better choice.