> It's been nearly 20 years, what are cryptocoins useful for? And not personally, I mean what have the cryptocoins done to improve the USA?

I guess for the USA as a whole it can be difficult to identify purely good effects, although the same can be said of things like social media. For individual holders, cryptocurrencies (not shitcoins mind you) have been a pretty decent way to hedge against a rapidly devaluing US dollar. Gold would be the same I guess, but gold is either risky to hold physically (and difficult to transport) or you are at the mercy of a custodian beholden to one or more governments.