There is a difference. For those of us living in North Carolina, our state is different than South Carolina. Just like we are different than Virginia. So when newscasters refer to the “Carolinas” we know they are mistakenly lumping us together.
The English colony of “Carolana” had all of us together in 1663, but by 1710 it was clear that the northern half was different than the southern half. Different in every way, and in 1712 the English crown recognized North Carolina and South Carolina as separate colonies.
And the dividing line between the two? Well, that is another story.