The article says the images are 8 second exposures, no mention about composites. Are you sure?
What does seem interesting (to me), is that if you do the same and watch the opposite (right) edge, you'll the stars on the left edge are travelling right (and upwards), and the stars on the right are travelling left (and upwards).
I find this novel because I've never seen this myself - I'm in Northern Europe, so what I see is stars spinning around the pole. The effect we see here is the camera pointing towards the equator, putting it facing east(ish).
Regardless, this is one area where I'm happy to defer to natgeo's ability to spot shenanigans.
my bad - and here, i made this as a mea culpa to show that it's legit: https://i.imgur.com/aTvpilo.gif