While they can be a good tool, they can also be an easy trap for debt. People who use credit cards spend twice the amount people that use cash spend. Credit cards "points" suck you in but at the same time can be useful for essential bills.
Do not get tricked into thinking you have 0% interest because before you know it, it is actually at 15%.
Credit cards at the same time can be a great way to build credit. A few rules.
1. Have the money you are about to spend
2. Never spend money you don’t have
3. Pay off balances twice a month. This will psychologically help you make sure your balance is paid in full and may also help increase your credit.
4. Do not close old credit cards. Having larger lines of credit will help increase your credit score.
5. Utilize points and rewards they offer for purchases you are already going to make. I was recently booking a vacation and took advantage of the 3% reward my credit card offers. I was going on the trip anyway, so might as well save a little bit extra on it.
Bottom line: Credit cards are useful tools when you stay disciplined.