But why? The credit card is strictly better isn't it? I thought the main reason people used debit cards was that they got one automatically with their checking account and just never bothered to apply for a CC, but that's not the issue for you.
And yes, it can be easily worked out but I guess I just can't be arsed. And for purchases under £100, credit cards offer no additional protection whatsoever, so for my daily shopping I'd just be making my life more difficult for no reason.
They offer better protection against fraudulent charges though? If your card gets skimmed it doesn't matter whether you were paying £5 or £5000.
This means for example if you buy a flight and the airline goes out of business, your credit card provider will need to refund you. Also if goods are faulty, you now have two possibilities to get your money back - and the credit card companies are usually more amenable.
What exactly can a credit card do better than this?
the key difference is with the debit card it's your money that's been stolen, whereas with a credit card it's the bank's money