I agree with your other points (including easier customizability), but have to completely disagree with this quoted sentence.
In my experience of using macOS/OS X/Mac OS X as well as Windows and Linux, macOS is one OS where a user cannot avoid using the mouse or trackpad!
On Windows (and mostly in Linux too), I can navigate the entire system, application menus and UI controls without touching the mouse or trackpad, relying only on the keyboard. The same on a Mac would be frustrating because keyboard navigation, especially for menus, is cumbersome. There are many Apple apps that cannot be completely controlled just using the keyboard either. There are many UI controls (including in dialogs) that just need a mouse or keyboard. When I find these instances, for me it's like death by a thousand paper cuts (note: I do have preferences set to navigate through all controls when hitting Tab).
If you disagree with my assessment, please try this using only the keyboard (no mouse or trackpad) and see how cumbersome it is (not to mention inconsistent in certain ways with the rest of the system too):
* Open System Preferences
* Open the Keyboard settings (just an example)
* Navigate from one tab to another within the settings
Of course, I'd like to know how something like this can be done faster using the keyboard.