I think maybe they did it to stop the Makedones from rolling over the Getai. Chevrons play a huge part in AI vs AI autocalc battles.

Historically the Getai survived until the late Roman Empire, so it's not historical for them to be wiped out early on.

The Super Getai do for the AI Makedones what the Super Elutheroi north of the Alps do for the AI Romans and Germans - hold them back and force them to expand elsewhere.