I'm in the UK, and use one (IMO) sensibly. If there's a larger purchase I'll often find a 0% credit card and use that, then pay back. I only do this for stuff I could afford to pay back immediately if required.

Secondly, I'm not sure outside the UK, but we have something called Section 75, if I buy something and spend just £1 on a credit card, they are jointly liable for compensating me if something happens. If I'm buying a car, or large purchase I'll often pay £100 on a credit card just for the extra protection.