As most things, they are both a scam and a tool. It is like a gun, if it is pointing your way is probably something you would not like.
Cards are a tool when you use them to buy stuff you need to work or go to work or somehow produce a return or if you make sure you pay everything at the end of the month. If you do anything else, particularly buying stuff you do not really need (really really need) and then pay the minimum... you are going to learn first hand what is that people talk about when they speak of the "rat race".
Besides that, I might be helped a little by things like this because credit cards can be used when in an emergency which you can't avoid. Credit cards can be a tool that helps you make payments in these conditions if it happens that cash is difficult to obtain quickly or is not available but you need something urgently.
Even though there is a small additional fee, it's actually quite worth using it for several times in a forced situation