When I first heard of cryptocurrency I was reminded of when people started idling in Team Fortress 2 to get content drops. It was such a daft cart before the horse approach, but of course those dropped items could be sold for fractions of a penny and people can be dumb.
It also reminded me of Folding at Home. Here people completed by virtue of their personal compute resources.
Of course crypto serves as neither a form of entertainment or scientific discovery and is just a massive waste of resources to create artificial wealth. If only all that computation did something useful.