Can someone explain to me why this wouldn't have the perverse effect of discouraging the use of conventional bank accounts and causing people to just hold onto their cash or to put it in the equivalent of safe deposit boxes, or for wealthier people, to use "offshore" banks or to purchase assets easily convertible into cash?
India's approach was to cancel large-denomination banknotes, but it did not have the intended effect, https://archive.ph/ynouY > India’s prime minister, announced in November that Rs1,000 ($16) and Rs500 notes would no longer be legal tender, he suggested that corrupt officials, businessmen and criminals — popularly believed to hoard large amounts of illicit cash — would be stuck with “worthless pieces of paper”. But…
The objective was not to cancel large-denomination banknotes, given that even larger notes were issued in their place (2000 Rupee notes). The printing of those notes were well underway when "demonetization" was announced. The goal was to understand how much cash remained in the system, and to move away from a cash-based economy.
Just as most government programs, results are mixed. It seemed more of a failure immediately afterward, but with 6 years of hindsight doesn't seem as bad. It kicked off India's digital economy, with UPI digital payments finding mass acceptance. UPI payments went from $1.5B in October 2016, to $10B the following month. This triggered mass adoption of phone payment apps, and the transaction value stands at $140+ billion per month as of today. In most tier-1 and tier-2 cities in India, you don't need cash or a credit card to survive.
As far as tax evasion is concerned, while it wasn't any sort of total success it did pave the way for more transactions to flow through monitored digital channels. Today banks don't accept any significant amount as cash deposits and there are strict caps on annual cash transactions. Overall, the "demonetization" event of Nov 2016 was imho a success as far as the government's objectives were concerned.
As a private citizen however, I don't particularly like the privacy problems that tag along with this.