Sorry I don’t buy that argument about the A8 in the ATV4. As others have pointed out the chip (or rather the PowerVR GX6450 GPU) must decode 24P video because that is what Apple streams to it for movies. If the HDMI circuitry can’t output 24P then that’s a different matter but the ATV4 is HDMI 1.4 compliant so should have no issue with this. I have no reason to believe Apple couldn’t enable 24P on the ATV4 from a technical point of view.
The other arguments about HDR processing and power use seem perfectly valid.