This is a trap I've seen many technical folks on HN fall into - they define "useful" along the lines of "beneficial", or "productive", or "worthwhile", rather than simply "is used". Think of casino tokens. They have no intrinsic value, and can only be used within very limited set of environments, so you could think of them as useless in the strict sense. But that doesn't stop large numbers of people using large numbers of them on a regular basis, and the operators make hundreds of billions a year from the people using them, so they are "useful" in the sense of "being used" to serve a strong human desire (just not to make the world a better place).
So, sure, cryptocurrency startups can innovate a new way of making money. But it doesn’t make them useful. One could argue it doesn’t even make them not harmful.
Those are huge valuable use cases. However it doesn’t follow that we should necessarily facilitate those uses.
To my thinking, provably fair casino games are a useful innovation that sprang from cryptocurrency. Decentralized poker is another. If you find the entire global gaming industry useless, then I guess those are also useless innovations. Again, that's a value judgment.
I don't think it's fair to conflate the people/businesses trying to profit from the crypto speculation craze, pyramid shemes or shitcoins, with e.g. businesses that want to accept crypto to avoid paying a % of their income to Visa. Yet that's what this law would do.
Very good point about the provably fair casino games. I didn’t even know they exist. However note that casinos are regulated too - you can’t eg serve minors.