I believe paper money will disappear over time naturally. In the same time bitcoin can overtook fiat currencies and many people moved over to that.
I agree that there may be paper money began to be abandoned by many people in the world, and probably will dominate the digital money. but I'm not sure bitcoin can replace fiat
We should be optimistic about digital currencies adoption, because many countries started regulating Bitcoin exchanges like Australia and some American states,therefore, digital money is on the right way.
Digital currencies are still developing, and the paper money at the end of its development. But still digital money can not replace paper. Many countries are not ready