Cryptocurrency is the future of all payment method due to the decentralized nature which grants financial freedom and power to the people. However, for it to replace cash or the Fiat, it will take years of awareness creation. Up to date, some people do not have access to internet whereas others do not know how to access it.
Smart-phone and internet accessibility is growing. SpaceX's project "Starlink" plans on using satellites to provide a global broadband internet service. This coupled with growing network bandwidth will allow for universal cryptocurrency use faster than we think..