For the big country like Japan and USA, i think paper money will dead and digital money will take it. But for developed country, i think paper money will be used permanently.
I think you mean undeveloped countries which can't afford to set up the digital money system. For all other countries which can afford setting it up, digital money will be their only option.
I agree with him, in more advanced countries we are seeing that people are already using Credit cards for their payment, and are preferring digital system over paper money, so when bitcoin will establish they will all go to bitcoin.