There is no future for fiat money,paypal,skrill,perfectmoney,payza,payeer,payoneer and and other fiat money online wallet there are past.There is only future for cryptocurrencies which everybody almost likes
I think in future paper money will still be the same because we are using bitcoin as a option we can not spend bitcoin directly to buying anything so new generation will still prefer to use paper money as bitcoin can be complicated for them so they will use paper money as they are using..
for bitcoin myself I agree that it might just bitcoin will become an option for the fiat currency in the future, but I think that paper money may be lost or replaced by something sophisticated than fiat own future
That is easier said than done, by doing it, you will have to sacrifice the majority of users in this world. Paper money is the most convenient means to use for transaction and people has been using it for many years. Although we are moving slowly into a digital world but this people must be considered, thus, digital currency alongside with paper money will exist.