Nothing. These people will remain illiterate. Sadly, that's true. Progress is unevenly distributed throughout the world, and this is quite natural. Therefore, these people will simply continue to use their national currency. And I don't think it's going to be a problem for them, they have bigger concerns.
They say crypto/bitcoin is the future of money and it will soon replace fiats therfor even iliterate people will forcesibly learn themselves on how to use it because they will only suffer at the end .
The problem of such people is not only in the use of cryptocurrency, but also in the use of technology in general.
what technology are you pertaining to ? Cellphone , internet , computers ? Well these stuffs are now easy because many models are now being built with user friendly features so that even dumber person can also understand and learn on how to operate them because in our current world everything is evolving into a new digital era .