If the government has to regulate cryptocurrency for it to be useful as a currency, then it's not very useful as a decentralized currency, is it? In my view, most cryptocurrencies (bitcoin, at the very least) are built on fundamentally unsound economic principles which incentivize hoarding and speculation.

Well yes because the US dollar's value is regulated by economic experts. Bitcoin's core idea was always based on pseudo-economic monetary theories

Sure. GP wrote "found more use" - it's about relative not absolute value.