If it was tulip mania there would be no utility.
Dot com bust is a better example.
This is just the same. No one can just create their own currency out of thin air the way these are being created. To be a currency something has to be able to be used a store of value and a medium of exchange.
First, something that can go from $1000 to $20,000 in matter of months and then back down to $6000 cannot possibly be used as a store of value, way too volatile. Bitcoin (and any other crypto currencies) fail completely on that alone.
Secondly, to be a currency it has also to be used as a medium of exchange. None of them are. The only reason anybody buys a crypto currency is because think they will be able to sell it to someone else for a higher price. Textbook definite of a bubble, same as tulips, same as tech stocks in 00.
Finally - the USD is valuable and the Syrian Dinar isn’t because the USD is guaranteed by the US Gov who has assets and raises taxes. Crypto currencies fail on that as well.
Complete house of cards.
You’re just betting on black and hoping it doesn’t come up red.