Is there any reason NOT to apply for an Amazon Visa card?

Is there any reason NOT to apply for an Amazon Visa card? A simple question, really: is there any risk to getting a credit card for a one-time discount and then never using it again? I'm a student with a little (positive) experience with credit cards. My current card is set to expire in August, though I'm sure Citi will try to bring me back -- but this isn't really relevant. Amazon will give me a $30 discount (as they offer everyone, I think) if I sign up for their Amazon Visa card -- Student or Regular type. Is there any reason not to sign up for it, get the discount, and never use the card again? Would it make more sense to start using this Amazon Visa card as my regular, everyday card? Its terms are among the best I could get as a student anyway. Please don't preach to me about credit ratings unless you actually have a firm understanding of how they're assigned; I've gotten too much advice from people who don't actually have any more knowledge of the system than I do. Thanks.