Because you don't want to piss away half of your GPU/CPU performance on sections of the screen you won't be looking at? - Valid, but there's other options. This monitor has picture-by-picture.
Because you value the health of your neck? - This would be replacing 2x 27inch monitors, so no change.
Because the size of the display will be a detriment to many types of games that rely on having the entire FOV being seen without much eye-motion. - Same as above, just put it in picture-by-picture mode, or make the games windowed and use FancyZones.
Because you know that HDR1000 with only a couple dimming zones is a joke? - I don't care about local dimming on monitors and don't understand the people who do.
Because many games won't support the aspect ratio, and far fewer will actually benefit from it? - This is just repeating yourself at this point.
Because VA panels at 240hz will look like dogshit in motion? - This does not appear to be the case from everyone who's gotten a review sample. Alternatively, even at 120 hz this thing seems fantastic.
Because the response time is a lie? - This does not appear to be the case from everyone who's gotten a review sample.