That is exactly what debit cards do. When you make a purchase the money is withdrawn from your account.
The only novel thing here is you are deceiving the processing networks by claiming your debit card is a credit card. My credit union tried to do the same thing many years ago (as a way to build credit for students) and it eventually got caught by the processing networks and recategorized. Within a month or two it dropped off everyone's credit reports and they were back to square one.
From my reading, you're spending your own money, but to the credit tracking side, it looks like you're spending on credit and paying it back without incurring a fee. Clever idea, as long as the credit system continues to work like this.
How exactly is your card different? Is there no obligation to make payments? If so, how many cards can I open?