No, it is still credit. It's a loan for less than 30 days with no interest and the entity loaning the money gets its fee payment (2-5%) from the business you used the credit card at.
I understand the basic mechanisms of credit cards, and like I indicated above I'm not going to get into a logomachy over what should be counted as using "credit". These days almost all movement of capital involves "credit". Unless you are using cash you are using a form of credit.
Of course, not all credit is created equal and there is a world of a difference between using a grace period (which is not unlike any non-cash transaction) and actually spending beyond that billing cycle's means.
So yes she's using "credit" just like anyone does unless they pay in cash for everything (even checks are a form of credit). But that's not the kind of consumer credit and consumer behavior that is being impacted at all in what is discussed in the article and that kind of behavior isn't what's being referred to as a "credit card economy". After all, as long as she's paying her balance monthly her payment deferrals aren't inflating the overall money supply
in the way that those who don't do.