Paper money is getting old day by day. We are in a completely new era now. We are living in a digital world. People have started to use credit cards etc. more than paper money from now on. Because it is easier to carry and you don't need to calculate anything while you are making a payment. You just hand over the card and actually you don't even need to do it either. Now we can use contactless cards which makes things much easier for us.
And in the future, I think that we will stop using paper money for good and start using only digital currencies.
that's how civilization works, many changes occur with the development of technology. even now purchase transactions can be done with just a barcode scan, so many are taking advantage of e-wallet or e-banking. especially during this pandemic which makes us have to reduce physical touch with other people or objects that have the potential to transmit the virus.
Currently, cryptocurrency has not been fully accepted, the main obstacle is that it is decentralized, cannot be fully controlled by the state, that is the reason. but I believe one day cryptocurrency will become a very effective payment alternative, the government could improvise by making its own crypto currency.