There is a probability that maybe Bitcoin could be a global currency in the future. As long as adoption goes in a positive direction, it can happen. And, the rate of crypto adoption every year continues to increase, this could be the reason for crypto being used as a global payment. From the level of widespread adoption and acceptance it is easy to presume such things can happen. Cryptocurrency and Bitcoin is already growing, so if there is going to be a global digital currency in the future, no doubt it will be Bitcoin. Maybe there's a lot of issues on it but still BTC overcome those issues and still continue to be unique among other currencies.