If it were the case that the main currency of every country in the world is Bitcoin. Then how do you think the world economy would be run? Because when Bitcoin becomes the main currency, the American dollar and other countries will have Bitcoin as their main currency. The local currency of that country will be associated with it as the second currency. In this case, how would Bitcoin be used or how can it play a good role in the world economy?
How can Bitcoin become the currency of every country in the world? How would people be able to pay for everyday purchases? Bitcoin wasn't designed for that usage, so it's really impossible for it to be a global currency. Even if we enforce it and even if everyone knew how to use Bitcoin, people still wouldn't be able to use it because its block size limits the number of transactions and when billions of people create a transaction in a single day, it will be clogged for months or years.
If we want to develop the world economy, we should work hard and be fair. Bitcoin can't magically boost any country's economy because in the end, it's product and the service that generates value.