It's very far enough for bitcoin to be the international currency. Because bitcoin has requirements to use so basically bitcoin can't use by just a normal person to use the person should have a smartphone and a internet to use bitcoin and to spend it same with the store that he or will be buying at. So not all people have that especially a normal market and small businesses. So that is impossible for bitcoin became international currency.
Not sure how is a smartphone and an Internet connection a big deal. I'm not just thinking of major countries like USA but third world countries have a pretty decent Internet connection. Even when you have a quite slow connection, using bitcoins don't need that much Internet usage since you're basically just sending a response that you're about to send bitcoins to another user.
Bitcoin is definitely possible to become an international currency. If bitcoin grew that much, then the technology probably has already grown much more than what we have right now. By that time, someone has already thought of a way to put an Internet connection to civilized places. There's basically no point to put an Internet connection to undeveloped or uncivilized places since there will be not much people transacting there.