sooner or later I'm always sure of that, big countries will agree with bitcoin and serve as a means of payment,
and if that has happened then a small country will follow and eventually the BTC will be adopted en masse.
Fortunately, smaller countries are even the ones that are accepting the use of cryptocurrency more than the larger countries, so it is not going to be a new thing to them when the big ones eventually chose to accept it, and I even think that it is smaller countries that are influencing the bigger ones already since they have tested and implemented it and the bigger countries like America, china and India have seen that it has not affected them, their economy or their power over their citizens in a negative way, they are beginning to have a soft spot for the cryptocurrency.
I am quite certain that countries like America will be regulating it very soon and since they regulate it, that would be the beginning of cryptocurrency wide spread in the whole wide world.