Possible? Yes. Will it happen in yours and mine lifetime? Probably not. Currency is a man-made token of exchange medium. The reason we keep having different currencies is because of geography, politics, religion, ideology, natural resources, etc. amongst many other factors.
However, the one thing society cannot agree in general is wealth token. It is a man-made tool that is used for manipulation. The start wars, to have brother turn on brother, to have civil wars because of it and to dominate and subdue other nations that have a weaker currency than yours. We also use it to bully others.
Puritans would like us to believe that cryptocurrency is the answer (and I would agree), but not in the whole sense. The practical side of things is such that we mankind cannot change overnight and agree to such equality. It just won’t happen. There
Possible? Yes. Probable? Not in our lifetime.