The maximum numbers of bitcoin to be mined is 21 million bitcoins. Bitcoin can not be used as money by the whole world because it has a maximum cap. My opinion . What is your stand ?
Bitcoin has the liquidity so one bitcoin cn be divided into so many parts and it maybe enough to handle 7 Billion people of the world.But we don't have only bitcoin as the crypto currencies and other thousand more crypto currencies are also available so it can be enough to replace the fiat money system.