I was about to nitpick that, then realised one can fake long exposure with a sequence of pictures.

The author mentioned car lights doing light painting, which is achieved by compositing at least two pictures (one long expo for lights, one for the car which would otherwise be blurry as well)

Can be done in one shot with flash activating at end of exposure

True! One could argue it's a very physics way of taking the second picture + performing the composition ;)