Max Nozin, I am sorry to see you still advocating here on behalf of crypto currency, (blockchain could potentially be a different situation). Currencies of sovereign nations, as we know, have problems enough and can only be a strong as the "full faith and credit" of such a national entity. Cryptocurrencies have not even that to back them. They will be completely susceptible to market manias and even more so than say "tulip mania", which at least had an entry cost.... that is some tulip breed or another was being bid up to unsustainable levels. Cryptocurrencies, in other words, have all the defects of any currency and even more, since there is no underlying value, no backing asset, no "faith and credit", no 5000 year tradition of desirability as an asset such as gold... which still costs quite a lot to mine and hence "create" as a currency. No restraints on cryptocurrencies, in spite of the argument "out of nothing" you seem to propose. Public gullibility is the only restraint. Bitcoin supporters do NOT "have a valid point". This is completely self-serving blather designed to "pump" the market. We only need to wait for the "dump" phase.
Some aspects of blockchain as ledger technology may well turn out to have value to nation states, banks or international markets, but only after extensive development. Cryptography progress is always just a few of steps ahead of computational power and/or decryption algorithms-- it has always been and likely always will be... look at the history of cryptography and its important influence on the outcome of wars.