The comments on this site thus far make a lot of financial sense. Credit cards are an atrocious was of managing long term debt and should not be used as an overdraft facility unless some disaster has befallen you.
However, clearing your balance every month means that you pay no interest and the money, therefore stays in your account, earning/saving you interest until the bill is cleared.
Also, using your credit card in this way for ALL of your monthly expenses (instead of your debit card) allows you to see exactly how much discretionary spending you are doing every single month. It can be quite a shock and really helps you manage your spending as it is easy to see at a glance how much you have spent over and above your direct debits and standing orders.