Yes, it does. The "shadow" isn't a shadow, it is a preview of what your mark will look like, before you actually make the mark. So if it isn't aligned how you want, you can rotate the stylus in your fingers to get the angle you want before drawing.

I'm not an artist, but this is actually useful to me even for just writing sometimes, e.g. when writing Japanese characters with a flat/bladed pen style.

You are right that the physical Apple Pencil stylus doesn't have the same geometry as the virtual pen/brush/etc it is modeling, so without the preview mark on the screen when you hover the tip of the stylus near it, it would be really hard to know what the angle was.

Perhaps some real artists could develop a muscle memory, because while the stylus tip is round, the body of it has one flat edge. In my quick testing, it seems that the angle of the virtual brush/pen tip stays consistent relative to the flat edge of the stulus itself, even across drawings and putting the styus away and taking it out again.

But for normal people, I think the preview indicator is very useful and easy to use — although not needed at all for many pen/pencil styles, since those also are modeled on writing implements with round tips.