I already talked about it, probably annoying some people saying it again, but:
I like the higher resolution without a doubt, and on bigger screens it actually would be preferable, but it's spoiled by HDR and 'cinematic' color grading.
Recently compared head to head a BD and UHD of Out of Sight, and to make UHD look as good, as BD, had to raise brightness, contrast to 100%, color and some other settings, and turn on contrast enhancer to high, while turning all of those down on BD to match the murkiness. And if I turn just the contrast enhancer for BD, it goes beyond anything UHD can reach.
You probably have some sort of cinema or theater preset profile on your TV, try it. That's how UHD looks to me in comparison to properly calibrated BDs and DVD playback. I don't like how dull movies look in actual theaters either, which I haven't visited for over 15 years, going back only a couple of years ago. So maybe I'm used to how 'wrong' DVDs and BDs look, I don't care. At least pirates still provide 2160p files without DV or HDR which I download.