For me I do not think that there is coming a big surprise for the paper money in the world because paper money will always be the number one paying method for the most people so i do not think you should worry about that.
Paper money is very hard to determine what is going to be its future. But still that is not a problem because people tend to use paper money.
And I don't think paper money is going to be out of the league when bitcoin gets popular at all.