It has nothing to do with looking “cool” and everything to do with practicality. Your 99% is bogus. I can think many reasons why dark mode is more useful for all sorts of task. To the extent that I’ll use it over light mode. Even my elderly relatives are most excited about dark mode as they work with photos. Inverting colours is no use because nobody wants the colours themselves inverted.Why is everyone so interested in dark mode? It looks strange, the ergonomics are broken.
It might be useful if you work in total darkness, but the clever solution is to work in a well lit room, which I sure hope most people do.
I tested it in the beta and found it stupid and immediately turned it off. It has zero use for 99% of the users, unless they want to look "cool". If you really need it now, just use "invert colors", available right now. That one even works better since webpages becomes dark too. Using dark mode mostly for web pages is horrible, a bright white page with menus and controls darkened so your eyes have to strain to see them. Not good at all.
Photos - white space around everything in photos has always been terrible and distracting, and blows out your perception of colours, the same applies to other creative apps and the finder itself when viewing thumbnails etc. There’s a reason every single DAM other than Photos is framed black and gray.
Bright webpages don’t look that strange surrounded by dark windows.