You don't have to be in debt, paying your credit card in full each month is an excellent way to build credit, and you will never pay a cent in interest as long as you pay in full without fail.

I can see how it all appears to be a silly game if you never actually need credit, however there are material benefits (cash-back, rental car insurance, etc) of playing the game. In some cases the benefits you receive are nonsensical until you realize they are subsidized by irresponsible individuals paying huge sums of interest. There's a special kind of smug pleasure reserved for those who are financially responsible in America.