[~Misguided Ghosts~]

I know some people who only use it for gas or they only use it for medical stuff.

Definitely a good point. There are credit cards that are specific for certain stores/places/etc too! While mine isn't specific to one store it is a card that people get for medical purposes only. But, some stores and gas stations also offer their own credit card that you can use, which may help limit you a little bit if you're afraid that you'll go on a huge shopping spree as soon as you get a card. Of course, you are still at risk of overspending, but now at least you've limited where you can spend.