I wonder if their choice to do that highlighting has to do with console hardware limitations - namely, that games must work on TVs, which have a wider range of image quality compared to modern computer displays. So the graphics can't be very subtle even when the game's overall nature would be best served by subtle.
And those computer displays already differ from each other a good bit. I downloaded one particular wallpaper that was supposed to have a flat black background. Its creator had done a lot of erasing with what he thought was a black brush, but was gray. Not very-subtly-lighter-than-black, but GRAY. The result viewed on a decent IPS screen was lulzy.