Over priced
The PoE HaT is massively over priced, instead of re-inventing the wheel they should have just purchased one of the existing PoE modules that are freely available on the market and left headers for that on the Pi (or built a cheap Hat for them).
I think this smells like an engineer designing in-house because they can, not looking at the market and finding the best value for the customer. "NIH"?