Paper money will probably keep being used in emerging countries for some time but in the rest of the world it will gradually disappear.
but i think paper money is not going to disappear so easily. most of the people of the world are still using paper money and they have no any other option ans most of them even do not know any thing about bitcoin therefore paper money is not going to disappear in near future.
Paper money can never disappear as you cannot expect that poor people would be having an choice of using bitcoins or credit cards for buying things and they will continue to use fiat as that is the only option that they have.
Poor people would really tend to use fiat because they already know it since in the beggining and fiat money is been used by all means on all nations and they would not switch into bitcoin for the sake of adoption because their capability to invest into bitcoin would not be substantial.