Plenty of places in NYC were going cashless before the city council banned the practice, which was a dumb idea as requiring cash is inefficient and less safe; you're not likely to stick up a store that has no cash, after all. I would say overall I probably spend $0 in cash in a regular month as 'cash only' places in NYC have significantly declined in the last 10 years.
Their issue was that some people don't have access to banking services so the practice discriminated against them. My thought was that rather than cling to the past we should just make sure everyone has access to banking services.
Regardless, Johnson does not say that he doesn't have a bank account, only that his only account pays no interest and so is not required to be reported. That being said, the idea that he also claims to have no retirement accounts and no other assets is almost equally alarming both ways. Either he's not reporting what he's required to or he's flat broke and vulnerable to untoward influence.