I got caught out by a thing like this, recently. (I'm on the east coast of the US.)
My kids had a day off from school, and it was a nice day to ride bikes. There's a small municipal park around 5 miles (8 km) away, with a nice mini-golf course and a grill/cafe next to it. They were eager to go by themselves, so I told them they could ride their bikes there and gave each kid enough cash for a round of mini-golf, a cold drink and some lunch.
The park was card only! While that has been happening more and more, I was not expecting that from a city park. Thankfully, they're not shy kids, and they persuaded one of the park employees to use a personal card in exchange for cash. But I was shocked. They're 10 and 13 years old... it had not previously occurred to me that I should give them cards of any kind.
But yeah you still give cash to kids.
But you've reminded me of a case I still use cash: on business trips abroad with a mixed group of people from several countries, most people put money on the table to pay their share.