Bitcoin is the future but paper money still have a lot of relevance now because population of people is yet to understand digital money. There has to be a wider coverage of the knowledge of crypto before it can dominate paper money.
I had many encountered this thread asking which better a paper money or bitcoin/digital money. Well, as of now they are both useful to us because when we get bitcoin we used paper money to claim our bitcoin coverted to fiat. It is really hard to replace paper money to a digital money because fiat is a traditional money which we can easily used.