I think in my country it will not happen to phase out physical money even there is already a digital money or credit/debit card. Not all knows how to use cashless method and it is a long process. Not even have a good internet connection. There's a lot to consider before phasing out physical cash.
It will happen, but we don't know when.
It is true that there are a lot of countries that are behind in terms of technology but they are also going forward. Before we even talk about digital currencies there might be the mobile wallets or mobile payment systems that would revolutionize. I don't know if the government or the people as a whole would accept Bitcoin and cryptocurrencies as a fiat since I am just seeing them as an alternative in the process.