It’s been a long long long long time since I ran across an established business that doesn’t take plastic. Typically that’s only pop-up things like street fairs and special event parking. (But then. the Canadian banking system is usually a few years ahead of the USA)
But again, to be repetitive, billionaires don’t need ready cash. They use their assets to offset any money they need someone to front them, and banks are happy to oblige. To see how this works out, take a lesson from Michael Jackson. He made money hand over fist, spent like a drunken sailor. Some spending was quite useful - he bought the Beatles’ catalog which was an on-going money-maker. He had a back catalog of his own songs, which to this day continue to make money. For any big purchase, he went to some banks somewhere and they were happy to advance him cash against future income.
However, he went too far. As I mentioned - in that first documentary, they not only showed Neverland in all its extravagance, but showed him walking through some artsy schlock shop buying this and that (African masks, 3-foot brass elephant, that sort of thing). He said “I want that, that, that…” and the store boxed it up, sent it to Neverland along with the bill. The banks began to get worried he owed too much. They started demanding specific security - i.e. we won’t actually buy the Beatles’ music rights, but you agree their income will be directed specifically to our loans first until they are paid off; about as close to a mortgage as one gets.
(When I was in Dubai and took a boat tour around the Palm, the tour guide mentioned that the room over the arch in the Atlantis cost $79,000 a night and Michael Jackson stayed there once for a while…)
Once he died (and so stopped spending like crazy) trustees sorted out his debts and income, paid down his loans, and his(?) kids are well off.
That’s how billionaires spend when they want to. They say what they want, and someone makes the arrangements for them, and unless they want to get involved, they are not bothered with the details unless it means significant changes in the character of their holdings.