Some pretty interesting industries have gotten bootstrapped with speculation though, and we are hopeful that more practical applications will develop in the future.
Same for the Internet.
As you admit yourself, cryptocurrencies are a solution looking for a problem. They do nothing, they provide nothing, they're just—"valuable". It's a scam, thousands of people will lose money, and you will have done your part to help those people lose money.
Could you please stop now? You're a fine HN commenter otherwise. It's fine to be skeptical about cryptocurrencies, as many HN users are—but it's not fine to do flamewars or break the site rules.
In countries that have problems with their fiat currency, non government controlled currencies are quite useful. Especially as crypto cannot be confiscated.