CGP Grey makes some great points in this article as to why iOS should feature a system-wide toggle for a dark mode, and why the Invert Colors accessibility option isn’t good enough.
I’m all for it. In just about every app that has the option, I have dark mode (“night mode”) enabled by default. This is for a few reasons: for one, I just love the color black; second, as I use a Space Gray iPhone, the black backgrounds seems to make the app “flow” with my phone much more nicely; and, most importantly, it’s just easier on the eyes and much easier to read.
Plus, black-on-white is just boring. (Yes, I realize that this very site is black-on-white. I’m working on it.)