Hey, I always do that too. I'd much rather have back more bills instead of a ton of loose change.
Nothing wrong with that.
Why do people even still use cash? That's what confuses me. Just swipe the card and be done with it. It's easier for everybody, and it doesn't leave you with coins rattling around in your pocket only to be lost later on. Not to mention that several credit card companies these days give you various percentages back, so you actually spend less by using the card instead of cash. (OK, yes, I understand some people don't have the self-control not to overspend and/or pay off the bill each month, and for those people, yeah, better not to use a credit card, but at least a debit card would still be faster and avoid the same problem.)