If you really think that the Myrmidon's supposed to use the Helios, then I have no comment. Or maybe I do, but that wasn't what I was arguing for, anyway.
If you really think they screwed up that badly in
not giving it the Harpoon, you're crazy. Somebody would have noticed in beta. If the Helios was simply the odd one out in the table entry for stuff, sure, I could buy that it's a mistake, but it's not; they also delibrately did not give the Myrmidon the Harpoon, which is a much more glaring and serious error if there are any errors about, and once they went to fix that they would have noticed the Helios was in there too.
But they didn't go to fix that. Everything, therefore, is most likely as it should be.