Credit can be dangerous for a number of reasons, primarily is that consumers can easily get overextended.
Credit is usually based on income. So, a person with 50k in income a year might be given a 25k line of credit. Or maybe even a 50k line of credit.
The end result is that the consumer might buy 25k in goods on credit before earning 25k in return and something might come up. Or they might lose their job. And then they don't have that 25k in money coming in but they still own 25k to the credit card companies.