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.
Yes, I think so, but we cannot see this will happen in the short time because we need each government from all country to accepting cryptocurrency as a new currency for their country. As you said, we need an internet connection to access cryptocurrency, and without that, the small country cannot use cryptocurrency. So it needs time before this could happen in the future and I think the governments need to build more infrastructure so their people can easily to access the internet.
We will not even see it happening at all. It is not like we can see the future though, but it is one thing to be realistic and know that no matter what government worldwide will not just allow decentralization which is what cryptocurrency is all about to just be in the front light for everyone to use and then getting to see fiat being discarded.
We all know how government wants the control and the way I see it, cryptocurrency will apparently just go hand in hand with fiat, while the space is regulated so as to curtail some negative activities within the space.