If you ask the conservative people, they will tell you that it is. If you ask the people who wants to move the country's economy, they will tell you it is actually a way to keep the country afloat. What if there are no credit cards and no one spends? It spells the death of all the shopping malls, holidays and tour companies, online companies and etc.
So, I would say that we do need credit cards. But of course, one has to have some discipline and be discerning consumers, checking out the credit card offers and make the right choice. If you are new to this, then, I suggest you read the useful articles on credit cards on this informative site.
I find those articles on managing money, how to avoid debt and how to spend wisely rather useful for those who are just starting out. As for me, the best is to keep only one card and make sure that we pay all the amount due at the end of the month without accumulating any outstanding amount.