Paper money is normal a good pay method but everything is indeed getting more digital and due to that we can say that it will disappear in about 20 years from now without any doubts.
yeah something obsolete will be replaced with something new, more sophisticated, I know that paper money is very easy to use, but the digital money will be easier and will replace it in the future
paper money will remain till last and it will not disappear even after 20 years but the use of paper money will be reduced much and maybe from some hands it disappear but will not escape from market and the use of bitcoin will be everywhere which is sure to happen.