It's mostly, probably good that younger people are increasingly eschewing credit cards, and I'm actually glad that the article didn't make these next points.
Credit cards are a tool, and a very useful one: having a couple/few, but not using them or paying them off every month increases your credit rating. They are helpful if you are tight for cash or have an emergency. They are generally more secure than debit cards...a big deal if you do lots of travel or online shopping. And, for "responsible" users, you should recoup some bonus (cash back being my preference) that is not available from debit cards.
Now, if having credit cards changes how much you spend, then it is probably a better idea to go without (or to have them for credit purposes/emergencies but keep them locked up day to day), but if you are going to buy something anyway, doing it with a credit card that provides some reward is the better way to go.