Transactions are recorded and kept for both cards.

Two differences. In the U.S., Debit Cards have passwords called PIN (Personal Identification Number), Credit Cards rely on signature matching as the primary mechanism for finding fraud. Ironically, a was speaking to someone who visited Puerto Rico recently ( a network installer for a major company ), and was required to have a PIN number for his Credit Card. Because signatures of Credit Cards are only checked at a few stores I frequent, I'm a strong advocate of PIN numbers, but I want them to be 6-8 digits, not 4.

The other differences is that, with a debit card, the funds are deducted from your account, and you cannot get money if you don't have money in the account, unless you arrange in advance for "overdraft protection", which you pay for with a monthly fee. With a credit card, you are borrowing money at some of the highest interest rates in the country, and must pay the entire balance within 25 days, or pay somewhere between 12% and 25% interest. If you don't remember to make at least some payment each month by the due date, you are charged $29 for your tardiness (that one makes me the most angry of all), which in one case for me a couple of months ago was more than the total balance on my credit card. (I'm really angry about that, too.)

There are some other benefits for credit cards, like additional insurance, purchase protection, credit life option, etc. but in the end you're really paying for all those "features".

But, my point is, if everyone is using debit and credit cards, then the folks using cash are "different". I'm not really concerned about things like whether you use cash for groceries, but I'm really concerned about purchase of big ticket items and use of cash when travelling.