It is my understanding the credit cards currently offer much better consumer protections than a debit card. Clark Howard has ranted a little about the lack of protections with debit cards. Something to keep in mind.
I don't know specific details on the policies or differences, but I do know that when my debit card number was suddenly used on about $800 in online purchasing, it really wasn't too big of a deal. I found out when I left work for lunch and saw an e-mail from my bank (Bank of America) saying they'd cancelled my card for potential fraudulent activity. I called them and was told I'd have to get a new debit card and that I'd have to wait till the charges finalized and posted to the account before I could request the funds back. All told it took maybe a week and a half to get the money back. For some people that could be catastrophic, but I think for most people here, it's easily manageable.
As a side note: This happened early on in our journey towards mustachianism and the way we were able to absorb that amount of money suddenly missing was an event that really cause my wife to realize just how much nicer and less stressful life is when you live on a lot less than you make. A friend of her's from work had a similar thing happen a few months later (with a similar amount of money) and she was extremely stressed out and upset for weeks... big difference.
I started paying these off as soon as I made a purchase a while back. Not so great for the credit score, .....
Not sure how this would affect your credit score. I thought utilization ratio was the important measure, not whether you pay off your balance. That is, the amount you owe compared to your available credit affects credit negatively when you approach your limit. When paying off credit cards every month, your average balance is simply your average charges. As long as your keep those monthly charges low compared to your credit limit, it will reflect positively on your credit.
It's my understanding that the utilization ratio gets it's numbers from the monthly statements. So if you spend $1,000 on a $10,000 credit limit and pay it off after you get the statement, then you have a 10% utilization ratio, which should be good for your credit score. But if you spend $1,000 and pay it off after every purchase, your end of month statement will only show one purchase worth of balance or probably even a $0 balance, giving you a 0 utilization ratio.
I'm no expert or professional, so I may be mistaken, but that was my understanding.