With your new, lower credit score, you wouldn't qualify for as favorable an interest rate. One scenario: Instead of 5 1/2 percent you would only get a loan for 6 3/8 percent. And the mortgage would cost you $50,473 more in interest over 30 years.
Bottom line: It's great news for certain debtors that credit card companies are willing to negotiate. But, if you don't really need to take such a drastic step, the repercussions will be costly and you won't be able to forgive yourself.