People like novelty. Dark mode is something new in UX design. I'm not sure I'd read into it any more than that until a few more years pass.
That being said, I have pretty good luck with browser plugins that auto dark mode websites reasonably well. I'm not sure I'd go redesigning the entire web with darkmodes in mind when plugins can do a good enough job.
For some people, yes. For others, no. That's why this should be a configurable option.
[citation needed]. Why do people keep making these general statements. Every time they do counter-examples immediately appear in replies. Why can't we all agree that we're all different and it's largely a matter of preference.