Well, this one was all Andrew's doing. He had a free (sick) day, while I had a midterm.
He's not a math a major, so I surmise he's not used to generic classifications, n-tuples, k-gons, etc. and would prefer direct names. As for me, I think that k-gon is okay (and better to use) for any polygon with at least nine sides. Everyone knows 3, 4, 5, 6, and 8. And seven makes sense. But once you get to something like enneagon, spell-check loses you, let alone the public!