For consumers, credit cards offer benefits, such as cash back, "point rewards" systems, and so on. The price is the same, credit or debit, so why not credit?
IMO, Most American got used to the life use the money in future. CC is the simplest way to loan money from the bank now, and pay it back in future. Meanwhile, the bank also like this, as lots of people wouldn't able to pay the debt on time with full balance, so they can make money from the interest.
