These can be an expensive way of borrowing as they often have higher interest rates than loans.
You can often find attractive introductory offers – 0% on purchases for 12 months, for example. If you can pay the balance off in full during that time it could be cheaper than a loan, and they may also offer other benefits such as free travel insurance or purchase protection.
If you have existing debt you may be able to transfer it to a credit card – again you may find introductory offers like 0% on balance transfers which may make it cheaper to pay off your debts.
There may be a fee for transferring your balance, so factor this into your decision.