Sweet, you explained it just as I would have.
But yeah it's good to practice like that because you learn firsthand how to use the correct angles and such to make your drawings (even entirely fictional ones) look "correct" and like they could actually exist.
Learning correct perspective can be easier when you actually have a real horizon to use as a vanishing point.
Having true lighting can help you learn proper shadows as well.
I suggest picking a very specific area and viewpoint, and draw what you see, just like the drawings you posted, but draw the same exact scene from the same angle, but at various times of day, that what you'll get drastically different shading on the same objects.