Paper money is relevant in the future through bitcoin transaction.
I dont think paper money will be remove in the future as this is
being used already. However, lets admit thats its really helpful
to all bitcoin users.
I think though true digital currency will be more popular in the future but I'm sure it will not be disappearing to make paper money, because paper money will always be needed for offline activities
If they change paper money to a digital system where paper money wont be used anymore then there would be no use of paper money even in offline activities, but no one can say for sure that bitcoin will be that digital system of replacing paper money system.