Of course, Bitcoin can be a world currency. However, Bitcoin is not valid in all countries. But seeing the popularity of Bitcoin,it will be the world currency for a time.Only the bitcoin has been known in all the countries, which could not make any other coins.Everywhere they are Bitcoin,world Currency Will be.
Good opinion and I like the way you think.
I agree with you that bitcoin will probably be a major global currency, but can replace the current internet payment system, instead of paying with a credit card via the internet that will ask for our credit card details, we can play anonymously with bitcoin.
If you look back on the popularity of bitcoin is very large, but I'm sure someday bitcoin will become the world currency after everyone believes in bitcoin.