Ok e-tards, if you hold zero fucking balance it can, and often times will not show you as having an open credit line, having no credit out decreases your chances of getting a loan or whatever it is you intend on using the credit for. Banks like it when you carry a balance, and you will be rewarded far more if you carry a 10 - 30% balance (yes, up to 30% is GOOD for your score). Sure you can pay it off every month, but A. Most new contracts will have 0% for a year any how, B. It will just take longer to build the credit.
I'm not gonna make this a pissing contest but do your research. In the line of work I'm in I deal with a lot of financial directors and shit, I have an idea of wtf I'm talking about.