Capital One Financial ( COF), the latest company to get hit in the lending crisis, "is an interesting situation and potentially a buy," Jim Cramer said on TheStreet.com TV's Wall Street Confidential Web video Tuesday. The credit card company "stumbled" on its North Fork ( NFB) acquisition "because they didn't really understand the mortgage market and they didn't really understand credit cards," he said. What Capital One wanted to do with the purchase was to "develop a steady source of money to be able to back up a deposit base." That is what Capital One did with its acquisition of New Orleans-based Hibernia, and then it did it with North Fork and got the GreenPoint Mortgage business as part of the deal. Cramer said he remembers speaking with Capital One's CFO off line, and the finance officer commented that the company doesn't really understand the mortgage business. "It is hard to understand," Cramer said. "They bought it at the top and they've taken the ride down. Why I'm interested in the stock is because the credit card business is holding much better than the housing business, and that's because it makes economic sense to walk away from your house, but not your credit card." When people walk away from their house, they go back to renting, he said. However, they have to keep their job, and, in turn, their car. They also have to be able to spend, so they keep their credit card. "The house is the expendable item."