I doubt either one of us are in the 'demographic' target. Looking through the "details" at the above link doesn't show much of interest to me. However, I did glean a bit of hope seeing this:
The menu bar is now taller and more translucent, allowing your desktop picture to extend from edge to edge. Words lighten or darken based on the color of your desktop picture. And pull-down menus are larger, with more space between the lines to make everything easier to read.
The mini-page preview of a Safari tab could be useful.
iOS has Dark Mode as an Option with or without automatic activation. The only strategic plan I see is to make the Mac as similar to iOS as possible. So, if it's in iOS already, it will likely/hopefully stay in the real OS.
I suppose making all the OS's use the same resources will make things easier for devs. Frankly, making apps useful for tiny screens on all iPhones is wasted energy when using even an iPad! I have yet to hear of anything useful for a watch-sized screen.