The US dollar exists almost exclusively as a cryptocurrency, and when cash is completely abolished that’s all it will be.
You can speculate in anything, but that doesn’t make the thing you speculate in bad.
Are tulips bad? Do people still make money selling tulips?
Bitcoin is up about 600% from this time last year.
https://charts.bitcoin.com/chart/price
I would be glad to hear about any investment that even has the possibility of a 600% year to year upside.
Buy a Bitcoin, turn it over and find there’s nothing there