I think countries similar to Germany could do this, for the rest of countries even in 50 years they will still be using paper.
Paper money will be the most used money in the world even after 50 years because there is nothing can replace paper money because it is backed and supported by the governments and a lot of people and businesses are using fiat as a primary type of payment method so there is nothing can break the future of the paper money.You are right in a sense that even if we have only bitcoins, there are still bitcoins stored in paper wallet, so we can not omit money stored in the for of paper.
The design or technology may change but people always want money to be in their hands and its the paper currency and paper wallet which gives them true satisfaction.