It goes down to self control. Of you are able to control yourself not buying useless things, there's no harm using a credit card. And it even gives you rebate around 2%, so why not
i think the best way is to have zero funds on your card altogether so you are able to spend anything, because by the time there is something i know you would spend on useless stuff
yeah I think by doing that you will be more difficult to shop. but make sure that you save some money later to buy food.
if you can keep your money in a place that is difficult to reach it will be better