I have used the card for small purchases when I have no cash on hand, but most times I do, so it doesn't happen often. I don't have any credit cards, but I have a debit card connected to my checking account, and that's what I use. I've seen people use credit cards (not debit cards) to purchase groceries. I can't imagine paying interest on your food.
If you pay off your balance every month, you don't pay interest on the account.
A couple of times a very long time ago--say, 30 years--I ran a balance on a credit card for a month, but the immediately following month I paid it off. Maybe I paid a little bit of interest, but it wasn't much.
But this is just the way I was raised. When I was a small boy, before credit cards were available to "ordinary people" (by which I mean working- to lower-middle-class people), my mother and father did have "charge-a-plates" at local department stores (and you had to be "approved" to get those, but I don't know what that involved). These were not revolving credit accounts; they were merely a convenient substitute for cash, and you paid off that balance every month. This is more or less how I use credit cards. I do so much shopping online now that I couldn't get along without credit cards, but I still pay off the balance every month. Put another way, I use credit cards the way my parents used charge-a-plates, as a convenient substitute for cash, not as a revolving account.
This is the thing about credit cards: Once they were made widely available, the companies that issued the cards suckered in a lot of people to buy stuff they really couldn't afford because they didn't really have to pay for it. All they had to do was pay the interest each month, and that's how the card companies made money--off the interest cardholders paid. It's been a while now, but formerly from time to time I would hear news reports about how many thousands of dollars of credit card debt Americans were carrying. I can't imagine living that way--really, it's living "beyond your means" (is that even a thing anymore?).
I make two jokes about myself: Credit card companies don't make any money off me because I pay the balance every month, and I'm the only person I know who still has the concept of "the grocery money"--I get cash out of the bank to use when I go food shopping. (Yes, I once--once!--used a debit card to pay for groceries because I forgot to put "the grocery money" in my wallet, but then as soon as I got home, I took that money off my checking account register, just as if I'd written a check.)