"Cash is untaxed" is a universal rule; there's a food stall that only sells deep fried Vietnamese eggrolls (and has for decades), they prefer cash; in part because cash is untaxed and they may forget to document every sale on occasion, but also because they do relatively low amount transactions (<€10), the €0.25 transaction fee does add up for them.
It's also why "knowing a guy" can be useful, tradesmen coming in on their off hours to do a job for cash.
In my country (euro-land), transaction fees are often brought up by shopkeepers as a bogus excuse, but in real life banks offer plenty of percentage-only plans without fixed transaction fees.
Yeah, "knowing a guy" is very common here, as in, hey, I know a plumber, I know an electrician, I know a painter, and this and that. It is always cash with them, of course.