I don't think the mark has anything to do with the money/currency system.
There are some moneyless communities all over the world, they don't care what currencies the world is using. Also, the word "sell" (4453. póleó) doesn't necessarily have to involve money, it also means "to exchange or barter".
Who will receive the mark? (pay attention to the words in Rev 13:16)
All, both small and great, rich and poor, free and bond
I am sure there are billions of people in the world who are too poor and have zero money to buy and nothing to sell. And when it says "bond", I think of the hundreds of thousands of Uyghurs enslaved in the concentration camps in China. For them, what's the point of receiving the mark? Mark or no mark, they can't even get out of the camps anyway.
And who will NOT receive the mark?
Rev 20:4 And I saw high seats, and they were seated on them, and the right of judging was given to them: and I saw the souls of those who were put to death for the witness of Jesus, and for the word of God, and those who did not give worship to the beast, or to his image, and had not his mark on their brows or on their hands; and they were living and ruling with Christ a thousand years.
I just think "no man might buy and sell" is not the key point of Rev 13:17, it mainly tells us we are all beast that's it.