Because the modern curreny is depending upon paper now a days. In earlier times people used gold , silver, Bronze coins.
We can ,at PRESENTFIND the scarcity of cash in ATMs It is because of scarcity of paper. And it was because of Vijay Malya ans Nirav Modi who had lots of money.
Though Modi starterd Demonitisation , it didn't WORK on rich people instead it showes an Impact upon Poor people.