The economic reach of Bitcoin is an interesting subject of discussion. In the end there will be a maximum of 21.000.000 BTC. BTC is a eight-digit number.
I suppose that a currency can only be leading if it has the possibility ta pay in small amounts, equivalent tot e.g. dollarcent or eurocent. This statement limits the range of BTC, will the satoshi be the future euro/dollarcent?
In that case the maximum money supply wil be BTC 21.000.000,00000000 is e.g. EUR 99.999.999.999.999,99 (by the way: interesting exchange rate).
The money supply in the Eurozone (M3) is over EUR 10.000.000.000.000
So without any constraints, the structure of the BTC satisfies the necessary condition.
Let's inventory the other constraints.
Of course the total supply for Bitcoin is limited to become a general currency. That's why it is digital because it will never be like Fiat currency in a sense that most transactions can be paid by BTC. I don't know how to compute Bitcoin in euro but one thing I know is that Bitcoin for online transactions and euro or dollars for traditional transactions.