[jandrese]

Ironically the particulars of this implementation make it much less efficient than a dumb bubble sort. Many Quicksort implementations have the worst performance on already sorted data, and in this case it will be run a lot on data that is already mostly sorted. It won't matter here because the data size is always trivially tiny, but it is something to consider in the real world.

[drfreckles]

Again, the need was not to implement an efficient sort. It was to implement an animation that pretends to execute an efficient sort. Also, quicksort gives a more interesting result visually.

[cratermoon]

There's also the overhead of quicksort compared to bubblesort, making it a poor choice for tiny sets of data.

In this case I understand the author's point is to have something visually interesting to show the work being done.