I think that Bitcoin can be use as a matter of fact to be globally accepted. What is your take and which currency can you suggest to be accepted globally?
I do not think that this will happen in practice. Bitcoin has many drawbacks, and altcoyins continue to develop quantitatively and qualitatively. Already, many of them have far surpassed bitcoin. Therefore, even people will use different types of crypto currency.
From the point of view of the states, the use of a single crypto-currency on a global scale is generally impossible because of the high volatility of bitcoin.