Saying credit cards are bad financial decisions is like saying getting a drivers license is a bad safety decision.
Beyond the fact that you can use credit cards to your financial benefit, simply getting the card has no consequences whatsoever. (Unless you buy into the 'you must keep a balance to maintain good credit' myth.)
Getting a drivers license is perhaps the worst safety decision a modern human can make. The reality is that your _average_ person, if they have something, will use it. Whether that's a drivers license or a credit card is immaterial.
This, of course, contrasts with something like a condom, where, if you are going to have sex (unlike driving, or purchasing on credit) - you are going to do it, regardless of whether you have the license/plastic (no pun intended) - so you may as well do it safely.
It's very difficult (impossible?) to go into debt to a credit card company, if you don't have a credit card. Likewise the vast, vast majority of people who don't have Drivers Licenses (by choice, as opposed to having them taken away) - tend not to cause fatal accidents.
People get drivers licenses in order to drive, and they get credit cards to take on debt, build their credit, or make payments quicker and easier.
Drivers licenses don't make people drive poorly nor do credit cards make people make poor financial decisions. If you're going to convolute the two through some form of causality, the argument you could make is that people who are apt to make poor financial decisions are more apt to pile up credit cards.
Your claim that getting a drivers license is the "worst safety decision a modern human can make" is pure hyperbole. What about not putting on a seatbelt? What about not checking their tires and brakes regularly? What about failing to adjust their mirrors? Those are the actions that reduce safety, not getting the license, much like buying that HDTV you cannot afford reduces financial standing, not getting the credit card.
I'll stand by my original comment - no other single decision that a modern adult can make, than driving (or riding) in an automobile, will more negatively impact their health, or more likely result in a fatality.
If you take a representative sample of people who do what you suggest (seat belts, mirrors, tires, breaks) versus a sample of people that I offer (people who just don't drive - I.E. Walk) - I guarantee you there will be far fewer fatalities and injuries in my group, particularly in the 15-44 age range.
This ties _directly_ with credit cards - in that if you take a sample of people who do what you suggest (use credit cards properly/responsibly) versus a sample of people who do what I suggest (just don't get a credit card) - I believe my group will be better off financially.
To be truly scientific - we need to do a randomized trial - take a good sized group - and bucked them into two trials for 20 years - one group without cars, one group with. Another group with credit cards, another group without.
I'm confident that the non-car driving, non-credit card using group will experience fewer fatalities and be financially stronger.
I'm not arguing that you _shouldn't_ use a seatbelt, and that it doesn't help you (it does!) - I'm arguing that once you've started driving/riding, you've already increased your chance of fatality in a way that wearing a seatbelt can't reduce.
Assuming you still need to get from point A to point B, driving is far safer than riding a bike in most places in the US. Granted this is mostly because everyone else is in a car...
I'm not sure where bus-riding fits for safety. Anyone got numbers?
If you don't read the details that's not always true. Some people get suckered into cards with annual fees. Also there is always a credit checked performed. If you sign up for a bunch of credit cards for the free incentive money, all those credit checks and 0 balance / high credit limit can have a (temporary) effect on your credit score.
While I think credit cards have great benefits (see stevenwei for an excellent summary), getting the card does have a consequence in my experience: every card I've ever had has an annual maintenance fee (perhaps not the case in the USA?).
In the us, few cards besides AMEX have annual fees. The credit card companies make most of their money on people who fall behind on their payments and end up paying a ton of interest, and i would guess that annual fees aren't attractive to those customers. New college students are a prime example.
While this sucks for the system as a whole, on an individual level it does mean that those of us who have a reliable income (or FU money) can use credit cards very differently. They provide convenience, consumer protection, usually some kind of 'reward' (travel points or such), and yes, a 30 day grace period in which you can do something else with your money though I usually don't think of it that way. In fact, from an individual standpoint the only reason I can think of to use a debit card rather than credit here is a complete lack of financial responsibility/will power.
If a purchase requires you to borrow money, seriously ask yourself if you need to make the purchase. Could you (the royal you) buy a cheaper car, borrowing less or paying cash? Could you sustain another year in your current living situation?
The problem with debt-financed purchasing is that while it expands short-term options if not managed properly it can severely limit long-term options.
One does not need a drivers license to drive. One merely needs a vehicle.
The fact that not having a credit card damages your credit score should be enough to make even semi-intelligent people realize that credit score is not a fair and equitable measure of one's ability to pay on time.
Beyond the fact that you can use credit cards to your financial benefit, simply getting the card has no consequences whatsoever. (Unless you buy into the 'you must keep a balance to maintain good credit' myth.)