The answer to your question is relative. Some persons will tell you that they spend more when they have cash because it is easier to spend. Others might have different experience. Financial prudence is not a function of cash or credit cards but self-control. You ability to spend on only what you need is more important than the payment channels.
Maybe your conclusion about the general advice most financial advisers give to people about being debt-free is based on your observation. And the advice people get from professionals is based on the peculiar experience of the person. There are many other reasons why people are indebted. Credit cards can be very helpful in times of financial emergency, so it is not bad to have one.