Credit card fees in America are >2%, debit (and CC) is limited to <0.3% in Europe. So it makes sense for credit card companies in America to take the occasional loss and give out all those gimmicks as long as it keeps people paying mini-VAT on every purchase.
That's before you get into the whole "you gotta build credit" perversion that has Americans go into debt en masse and pay horrid fees on that.
If you are in a relatively healthy financial situation, you can also profit off of the system with many of the rewards card benefits in the last several years. One example of this is: https://reddit.com/r/churning
That's before you get into the whole "you gotta build credit" perversion that has Americans go into debt en masse and pay horrid fees on that.