Yes, It can be expected that cryptocurrency will be a Global currency in the future.
The BTC will be the father coin and there will be a lot of sub coins.
Cryptocurrency is a unique kind of currency that has great potential.
It has an attraction for all ages of life. It has a great opportunity for those who want to do something and desire to step forward.
Moreover, It has equal chances for poor or rich for development .
This currency has brought a revolutionary change in the world of business and trade.
It promotes a positive activity also.
It's a bit of a strange premise to put forward. Bitcoin already is a global currency, perhaps more so than any other currency in the world. I would say that Bitcoin is more of a test scenario and will ultimately be supplanted by other cryptocurrencies in future that have more units available. Even with all the decimal places, as the price rises and the amount of coins diminishes, it will become less desirable as a functional currency. There are a few different ways it could go, it may eventually result in such large consolidations within ecosystems like Paypal gaining large control over transaction flows or people simply seeing better functionality in upcoming altcoins.