With traditional credit cards it's easy to mess up your credit score because it's easy to make impulse purchases that you might not have the money for when the bill comes due. Making late payments on your credit card bill can be bad on your credit score.
With the Green Dot Credit Card you avoid this dilemma because you can't spend more than you have loaded on your card so there are no interest charges or late fees. It is also easier to get this prepaid card then it is to get a traditional credit card .
If you want a credit card it would be worth looking into this card.