To me the main difference is future and past. Bitcoin is the future and the real dollar etc is past. As world is going to be digitized so there would also be need of digital currency which is bitcoin. So this is the start and in future our names will write in history that we were the very early users of this currency.
Yes it is a right that in future bitcoin is going to be one of the most popular crypto currency of the world as it is the need of the day, we can see that people are entering in the world of bitcoin and adopting it as currency as the new generation is looking toward the online business rather than using real money.