Everyone who is saying there is nothing wrong with cash is right. However, there is one major drawback to cash which is no longer a big problem in societies which are mostly cashless. Namely, if your wallet gets stolen and you have $300 in it, you’ve lost that $300 forever. If your wallet gets stolen and they get your cards, you can just cancel them and aren’t even charged for fraudulent purchases.
I realize that means less privacy, but I can’t afford to lose that kind of money just walking to the supermarket to buy groceries.