it shows basically that you can keep a balance and eventually pay it off. Which, in turn, further shows that you are mature enough to get "credit" from a company, keep a balance for awhile, and eventually pay it off.
Just using the credit card like it's your ATM card doesn't add much to your score. It just means you, right now, can handle the task of just buying waht you can pay for. It doesn't say much about your credit-borrowing-and-paying skills cuz you haven't handled any credit yet.