i think cryptocurrency will become the official payment system in the world. but i can not exactly which coin will be the official tool, BTC, ETH, IOTA or XRP,... no one can know.
Yes their are many currencies in the world but not only Bitcoin but also others currency could be included in payment system. Such as Bitcoin, Ethereum, Bitcoin gold, Bitcoin cash. Etc
No, Bitcoin, Ethereum, Bitcoin Gold, etc. are the crypcurrencies, your words can make others misunderstand your opinion. Currencies are FIAT like dollar, euro, JPY, CNY, etc. Beside that, cryptocurrency does not depend on management of the government.