A credit card feature that's designed for convenience could be getting some homeowners into deep financial trouble.

Who doesn't love free stuff? The promise of freebies, earned through the accumulation of credit card rewards points, is driving many debtors to find innovative ways to use their plastic. And the credit card companies are happy to oblige, by offering to cover some of your largest household expenses.

Earning points by trading debt

Major credit card companies now allow qualified accountholders to pay their household bills-including their mortgage payment-on their credit card accounts. It's intended to be a convenience feature, as well as a way for responsible borrowers to maximize the accumulation of rewards points.

It began back in 2003, when select American Express cardholders were given the option to charge their rent payments. The program was popular enough to be expanded to mortgages a few years later. Visa has also launched its own program, which provides for the payment of both rents and mortgages.

Faux cash windfall

For most homeowners, the mortgage payment is the largest monthly expense. The idea of skipping that payment once in a while can be tempting, but it isn't a smart thing to do-unless you intend to pay the balance in full when the credit card bill arrives. Otherwise, you're facing rapidly rising debt balances and the associated, astronomically high interest costs. It can also damage your credit score. It just doesn't make sense to start accruing interest on a mortgage payment that already incorporates its own interest costs. Simply stated, charging the mortgage payment because you can't afford it is a bad idea.

Credit card companies, recognizing the risk involved, say that they're limiting the mortgage-pay option to qualified accountholders. The ideal candidate is one who routinely pays down credit card balances each month, and has the ability to pay the mortgage in cash every month, as well. These candidates can reap the benefits of earning more rewards points and having more flexibility with the timing of their cash flow.

Still, some industry experts worry about how the increasing availability of these programs will affect an already unstable credit environment. Screening qualified accountholders doesn't prohibit someone from charging the mortgage in a financial emergency, for example. If the problem is short-lived, charging regular expenses might be a lifesaver. But if the bad times last for more than a few weeks, the excessive charging will eventually backfire. Credit card companies argue, however, that the feature isn't that much different than allowing cash advances-something most credit cardholders have been able to do for years.

Ultimately, it's up to you to make responsible financial decisions with your credit cards. If you have enough discipline, go ahead and rack up those rewards points. Just remember that you won't be able to enjoy the free vacation if you have to file for bankruptcy first.