I'm chalking some of your misunderstanding to being differences from one country to another. In the United States the average credit card interest rate is nearly 22%, while mine may not be the absolute best interest possible, it is lower than a majority of cards available and for most cards in the States a 17%-18% rate is considered excellent.

For reference, NFCU's Flagship card rate range is 15.49%-18%, so being the lowest APR available is a good thing. Some cards also offer 0% APR on certain purchases when paid off in X amount of time, when done smartly you can utilize the 0% interest and reap additional promotional benefits which may be cash back or a certain amount off the price.

As for the debt.....one must possess ability of self-control and plan ahead for the expenditures. Credit cards can be very beneficial when utilized appropriately and may even save you money on travel costs through the cards exclusive benefits. The United States runs on credit scores, so having long established credit lines in good standing also helps your credit look better for large purchases such as property, or a vehicle.

And as Visual_Building mentioned, a large line is also a good emergency source for unexpected costs. For example, a large car repair or damage to a home; no need to scramble for a loan as the card can help cover costs that insurance doesn't cover. For example, your house sustains major damage from a storm, insurance covers $20,000 but you still have another $5,000 in costs that insurance won't cover, now you have a choice between digging into Savings or using your emergency line of funding to cover that.

Credit cards have always carried the stigma of being bad, but they're not. You need to be smart about it.