I completely agree that crypto will be the currency of the future. Cryptocurrencies are already used all over the world and constantly more and more countries begin to legalize cryptocurrencies and recognize them as official currencies, this is just a matter of time when the whole world will already fully begin to use cryptocurrencies with its full potential.
the possibility of cryptocurrency becoming a currency in the future could happen, but if that happens then only a few cryptocurrency will definitely be recognized (one of which is BTC), because in my opinion if all cryptocurrency are recognized then too many currencies will be used, therefore in my opinion only a few cryptocurrency are legitimate as currencies in the future if cryptocurrency has been legalized.