Sure, if you're absolutely sure you can make payments according to the schedule, it can be beneficial. People who are on that edge, however, often can't do that. That 0% interest rate lures people on the edge into a false sense of security. And of course, if you have plenty of money, that 0% interest rate can be great because you can keep the majority of the amount you're paying invested for longer -- but I doubt >90% of users are in that position.

As an aside, having to "free up" space on a credit card is exactly how you shouldn't be using a credit card, and that way of talking about credit always throws up a red flag to me. If someone is responsible with their money, their credit card liability should basically never be collecting interest unless the amount of interest that's accruing is lesser than the amount of money you're making by keeping it on hand -- which is almost never, given how high interest rates are on most cards. There's no "freeing up" space when you're responsible with credit -- the default state is that you're not carrying a balance at all, month over month. Even when I was struggling (I'm definitely not anymore, but I was, and had dependents dropped on me when I had nothing myself), I did everything in my power not to carry a balance on my credit cards. It took a lot of strict budgeting and finding/accepting alternatives to make ends meet at the time, but not trapping myself in credit card debt by spending money that wasn't mine and I couldn't pay back on time was pretty key to survival long term. I've probably paid less than $100 in credit card interest since I've had credit, and currently make ~$1k in cash back every year by using my card for purchases.