I had a credit card for years before I even realized you could just... not pay it off every month? I still don't understand why anyone would do that. Even when I had virtually no money I just bought the cheapest food I could with my credit card and continued to pay it off every month.

Spending money you don't have just means you're spending more money with interest when you don't have money in the first place. Unless you know you'll be in a better place soon and you just need to make it there, you're just making things easier right now in exchange for making things even harder than now just a little ways down the line.

Credit cards should only be used to spend what money you already have, so you can build good credit to have when you start being more financially stable. Like, sure, we all hate the system that judges us like that, but we can better fight to change it if we're not homeless.