Honestly, It was too hard to predict when. However, we can never say NO to it as the development and adoption continues. It will certainly take a long time to see it happen, maybe 100 years (or even more). It can be shorter if we see the most significant reason for switching to digital currencies but for now, we haven't seen it yet.
I can't predict how many years it will take for digital currencies to normalize, but with this, I can illustrate that we need one to five new generations to accept digital currencies as legitimate global and local currencies without much question.
Just as I, who was born in the 20th century, did not ask many questions with Fiat money, why can pieces of paper be used to exchange goods and so on? Likewise, the new generation was born without doing much asking why digital-based exchange tools.
The circulation of FIAT money will gradually decrease in tandem with developments in technology and human resources because they will feel the need for digital money like we do with FIAT currency.
I know that it is possible that civilization is getting more and more sophisticated and people are starting to think about how to continue to make their lives easier.
But on the other hand, for now, the circulation of paper money, which has been going on for a very long time as a medium of exchange for buying and selling, is still having difficulties and even in some areas in small areas there are still many people who do barter and this still exists in several regions in my country.
This can only happen to countries that are indeed more advanced and whose citizens understand technology, maybe they can still do it, but if in underdeveloped areas, progress like this will be hampered and when paper money is not implemented, it will be even more difficult for them.
Maybe it's true that they do that because it is a culture that is maintained in several tribes in remote areas.
But with the distribution of technology and the distribution of internet networks, they will slowly keep up with the times.
Additional thoughtsThe circulation of FIAT money will gradually decrease along with the development of technology and human resources because they will feel the need for digital money as we feel for FIAT currency.