Saying that demonetization is disrupting black money real estate deals is... Not evidence of pain or failure.
Can you not imagine legitimate reasons for doing this?
A small business owner makes a deal with a property owner to operate the business out of the property on a payment plan where the profits from the business buy out the property owner over time. The customers of the business pay cash so the business pays cash.
The buyer or seller doesn't trust the local banking system (e.g. because they have seen recent evidence of not being able to withdraw their money from it).
The banks charge some fees that can be avoided by cutting them out of the transaction. Even small percentage-based fees add up to a lot of money on real estate sized transactions.
The seller is also the buyer of a different property and they or the other seller wants to transact in cash for one of the above reasons, so they would prefer to have cash from this transaction to use for the other one.
In theory the transaction could be made to involve the banks by everyone doing extra work for no reason, but at the margin that scuttles the transaction and even when it doesn't it still generates overhead that dampens the local economy makes peoples lives harder unnecessarily.
Imagine someone writing that anti-virus brings pain with it, because it has a negative side effect on programs that need to shim and redirect system calls. Yes, it does, because the vast majority of the time that use case is a virus. If that's all they wrote on that front you'd wonder if they really understood computers.
The article's point is that good people are using it too and getting rid of it hurts them as well -- or hurts them worse, because criminals have alternatives that are only available if you break the law (or have the margins that come from black market trading).
And people do make that argument against antivirus. It detects things that aren't viruses and not things that are. Half the non-tech people with Windows PCs have antivirus and twelve pieces of malware installed at the same time. So if it has high cost and low effectiveness then why have it?
You can then take that cash with you to your next real estate purchase, or maybe break it up over time -- maybe take less cash out when you deposit your paychecks, maybe buy larger small items with cash, maybe pay for part of your car with cash, etc.
And the only reason the local currency is so liquid is because there is one. If you got rid of it, people would start using something else and it would have the same liquidity because then it's the thing that people accept.
I've had to open and maintain bank accounts in India. (No more.) The only way I got anywhere was by threatening lawsuit, under force of a lawyer and New York State's financial regulator, in an American court.