Otherwise your point (and parents) is a good one - certainly a good indicator that you might really be onto something.
The only people here who still use cash are those who have something to hide.
A few years ago I went back to carrying more cash. I had realized that debt cards don't provide enough protection against the card info from being stolen (it could take a week to get your funds back). Credit cards have more protection, but after having to replace my cards multiple times, it was just easier to pay for my lunch and gas using cash and not have the hassle of contacting all my recurring payment businesses repeatedly.
[0] https://www.wsj.com/articles/SB10001424052748704471504574438...
That industry?
Las Vegas Casinos.
Cannabis is no longer illegal under Nevada state law. As Nevada has not achieved independence from the US federal government, cannabis is not, however, legal in Nevada.
This is important in he context of your comment because, given the history of the Las Vegas Casino industry, I don't think they would want to wave a red flag of what is—from a federal perspective—organized crime in the face of federal authorities.
So he talked to a couple of armored-car companies about setting up a pickup schedule, and they wouldn't touch the business because they didn't want to take the chance that any dispensary money would get intermingled with regular banking money when in the back of their trucks, and thus invoke the wrath of the feds.
Looking at the pile of cash they had, he just said "Why don't we just buy our own trucks?" and they set up a subsidiary that provides armored car services to the cannabis industry.