Now it is a question of when and how fast it will become more widely spread or more mass adopted or more ubiquitous as well as being accepted as payment for more goods and services.
Yes it's boundless feature has enabled bitcoin to become an international currency.
Another thing, bitcoin is boundless its because any person in the world who can access internet can access bitcoin.
And sure in 20 years time there will be a possibility that bitcoin will not only be a international currency but also the official legal tender when the world turns into a cashless society. It is clear now that the countries whose banks are about to fall, their citizens are purchasing bitcoins.