I use it for cash back. It helps to significantly offset sales tax for me.
Yes, the money is always coming from somewhere and arguably products might be cheaper without credit cards. However, it’s the game we’re in, so why leave money on the table?
For anyone downvoting the solid advice in the parent comment, please be aware that "cash back" has been a widely used term in some countries for getting a shop where you're paying by card to charge an extra amount to your card at the same time and give you that amount in cash. It was a popular alternative to ATM use here in the UK for a long time for example. However if you were paying using a credit card instead of a debit card then the same (often very expensive) charges and interest rates would apply as if you used your credit card to get cash at an ATM and sometimes people didn't realise that and thought it was a free and convenient way to withdraw extra cash (as it typically would have been if paying with a bank debit card instead).
Yes, the money is always coming from somewhere and arguably products might be cheaper without credit cards. However, it’s the game we’re in, so why leave money on the table?