It's so crazy to have credit cards, we call them that here in the EU too but there is usually not much "credit" on them and you're supposed to be on the plus side... What a wild idea.
Credit cards in the US are extremely easy to get and easy to fall into inescapable debt with. I went to a hardware store and signed up for one so I could get 0% financing on some appliances over a year. I asked for like a $2k card. I told them I made $30k a year and they gave me a card with a limit of $8k about 2 minutes later. Now my finances were never even checked, just my credit score. I could have easily lied and said I made way more to get a higher limit, because I actually did lie and said I make less so they wouldn't give me such a high credit limit. It would be very easy for me to get a higher credit than I have income I think.