Credit card is now a common thing in Indonesia, as it is in other countries as well. When people traveled to other places, they don't have to carry too much money on their pocket as with a single credit card, they can be used to pay lots of items they bought (as long as the limit still available).
For some people outside Indonesia, they usually have a good reference on how to select the best credit card bank issuers. It's an online credit card consultant, where you can get lots of information about credit cards available. Unfortunately, most of it's service doesn't apply (yet) in Indonesia, for example paying for gas. We usually use cash instead of credit cards