Yes, they are, but they are more like Santa Clause: only for those who behave well.
If applied wisely, 0% APR credit cards can be used for getting a free 6-18 month credit or even earning money on it by so-called “stoozing”. Stoozing is when somebody with an excellent credit score and no outstanding credit card debt takes advantage of one of the 0% intro APR offers and uses this money to earn interest on a savings account. But this tactic requires a lot of flexibility and perfect money management skills.
Regular customers can get a relief from interest and a free credit if they manage to pay a 3% balance transfer fee and pay monthly payments during the introductory period. See our list of 0% intro APR cards.