It's nonsense to speak of them being "worth" "billions of dollars" which not only don't exist physically but as a sustainable notion.
"Cryptocurrency" isn't the problem of course. The whole concept of finance is rooted on a collection of blatant lies - re everything from the "worth" of so-called "precious" "metals", to the lie that the amassing of any kind of wealth is anything other than a crime against humanity...

Incidentally, it can't be a coincidence that so many media people are now pronouncing the present Mrs Trump's name as "millennia" (with the theory of guilt-by-association in mind, I'm waiting for either "melanoma" or "melena" to slip out of someone's mouth).