paper money will always exist,it never have ending,you know so many countries use paper money for payment.
but i also believe that sometime paper money will not popular again,but it just on a big country like US,and never end in small country.
In my opinion paper money will disappear one day but that day is still very far away. Imagine in the next 100 years people will use paper money? I don't think so. This will gradually become the reality and we should accept it
Paper money will be a lesser part of the function of currency. I remember that Sweden will become the first cashless society. But I think it will not be totally cashless.