I'm not sure why a central bank would buy crypto currency. That makes no sense from a monetary policy standpoint. If they buy cryptos, they have to sell their own currencies, which makes the value of them go down. Since one of the primary goals of any modern central bank is price stability, their purchase of cryptos seems unlikely. I get and agree with his arguement about substitution of gold with cryptos as a store of value, but his central bank prediction is very flimsy.