I think in the coming two decades paper money will be vanished and will be replaced by the new form of payments , now in first world like euro zone,USA and Russia many prefer not to use the paper money , so only grand mothers\fathers believe else than that . i hope Bitcoin and other alts will play a basic role in the future regard to this .
You said everything what I thought. Old people are using paper money and mostly now everyone prefers to use visa/mastercard and mostly cards for payment, we can say that bitcoin can to strengthen it's position in payments system. To my mind paper money only will be in some poor countries because it needs time to make good economics in such countries but future of paper money will end mostly in Europe, Asia and America, it needs small time, not more than 50 year.