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
Well in my opinion , buying something that you considered as useless is not bad as you think especially if you really wanted to buy that certain stuff . We should only avoid too overspending , we have to make a plan or list of what we need for daily life and list of what we want to buy (vices is the good example), and separate a certain amount of money for the bill we have to pay .
I also don't find it bad to buy stuff that we want eventhough it is not that important as long as we have the capability to buy such stuff. Just make sure you are not overspending to the point that even your monthly food allowance will be spended. Knowing what to buy, how much to buy and when to buy is one of the key on good management ofyour money.
Right, we have to understand that putting a limit with our spending is necessary so we will be able to save. But not spending at all is stupidity, we also have to reward ourselves of the hard work that we are doing and that is only done buy getting our wants.
The system needs money to keep running. Our economy depends on the fact that people buy stuff. Sometimes even things they do not really need, just for fun.
Saving too much endangers the way our economy works.
Of course it's not whise to spend all the money you own, but a few extras every now and then are good for both, you and economy.