There are some benefits, but it does complicate the transaction significantly. It's no longer between two parties (a consumer and a merchant), there are now at least two more: a lender and a credit bureau.

And that's why we're in this mess to begin with. Credit card transactions are reported to credit bureaus (from a quick web search, it looks like debit card transactions aren't) and this normalizes the idea that your financial data should be shared freely amongst finance companies.

There's really no such thing as a free lunch, or a free loan. When someone offers you one, it's good to understand how you're going to be paying for it.