As currency: - Only when a substantial proportion of the population have their wages and salaries paid in bitcoin. - Only when it is possible and convenient to live one’s life with payment for everything using bitcoin alone. - Only when funds can be recovered after theft from a wallet or a lost private key.
As asset/investment: - Only when there is widespread trust and faith by most of the population in bitcoin as a competitive store of value.
The political project: - Only when the population votes in (or there is a coup) a libertarian government that will do away with fiat and banks. - Only when there is widespread acceptance by the public that the early adopters should rule the world. - Only when there is widespread acceptance that cryptos or their proliferation will not cause either rampant deflation or inflation.