> Third, you can see what’s under the stylus. This is essential to artists, of course, but it also completes a simple visual feedback loop in which you can tell what you’re touching.
When I first got my Wacom drawing tablet, it took me about an hour of trying out handwriting in GIMP to get used to this. As long as you hover the stylus only a few millimeters above the tablet, you can even see the mousecursor move around to where you're pointing (takes a little bit of practice, that).
So, while nice, it's definitely not strictly necessary that seeing what's "under" the styles happens on the same plane as you're drawing on.
When I first got my Wacom drawing tablet, it took me about an hour of trying out handwriting in GIMP to get used to this. As long as you hover the stylus only a few millimeters above the tablet, you can even see the mousecursor move around to where you're pointing (takes a little bit of practice, that).
So, while nice, it's definitely not strictly necessary that seeing what's "under" the styles happens on the same plane as you're drawing on.