Bitcoin is now the strongest currency and is used in the world's most free financial system, and it turns out to be the most appreciated currency of the year. This is evident from the many new tokens emerging to fund startup using blockchain technology
I don't think so its the strongest currency in the world. Bitcoin is a strongest digital currency for sure. Not the strongest currency because not many even now don't know about Bitcoin. Even people living in Urban areas are still not aware of its existence and few just heard about it.
Moreover its not yet globally acclaimed or accepted form of currency, few countries might have legalized it but citizens of many countries are still waiting for approval.