I think this is impossible because digital currencies are not known by too many people now and many of them still do not know the usefulness of digital currency and do not know how to get it.
Yes, many people do not even know about digital currencies such as bitcoin, ETH and so on. They have not even heard of it, banknotes are nationally recognized legal currency. It is a bit difficult for digital currency to replace legal currency, but I will still look forward to it.
Yes, I also agree that digital currency is hard to replace for the time being because they do not use electronic money because they do not have the Internet in some places and people who do not know it. But as time goes on, in the future, electronic money and virtual currency will surely replace banknotes slowly, but by that time, the electronic money is not necessarily Bitcoin or Ethereum.