I'm continually surprised by the political influence held by the thousands of tiny banks in the country. I must applaud the people behind the Check 21 Act: it's the combination of a neat backwards compatibility trick (if you want paper, we'll print it and send it to you) and political maneuvering that I must admire it. > Since the standard U.S. bank account is a checking account, even if it cannot write checks, it is…
Even without the bank giving the check writer the privilege of overdrafting, either the bank or the check recipient has to absorb the loss if they accept a check for which the check writer has insufficient funds (unless the bank goes after the check writer). By contrast, with a debit card, the credit risk is much less (since the bank knows before the transaction whether sufficient funds are available).
If anything, anybody accepting a check for payment and delivering goods/services before it clears is extending credit in a way, but that has less to do with the bank account and more with pre- vs. post-payment for goods/services.