The moment all the countries convert to crytocurrency would be the beginning of many amazing things to happen to the world and the financial sector, the process sending and receiving funds worldwide would become very fast and easy, it would lead to growth of businesses and make life easier for citizens of the world.
This will happen one day and I am waiting for that time anxiously but I think it will take long time and will not happen in my life because I am 43 years old, but I am sure that our children will see this new era and the use of bitcoin all over the world. Blockchain will take over the market in the future and the whole world will use only digital currency for their needs.