back when i played with these positioning knobs, i found that i got better precision if i clicked on the knob, held the button down, and slid my mouse further away from the knob so that i had a longer fulcrum with which to rotate the knob... the further out i moved the mouse on the fulcrum, the finer the precision i had...
my main use of these positioning knobs, at that time, was moving my view point when viewing from other craft in my sim... it was pretty neat to be able to select any other craft, AI or MP, and pop into it for a view of what they were seeing along their flight path... these positioning knobs had to be used since each craft has a different 0,0,0 origin point so you might pop up on the tail of one craft and then in the middle of the nose of the next one... i will say that watching an AI craft landing from a first person perspective, say from the craft's nose landing gear, is quite interesting...
i do, however, agree that being able to simply type in the desired numbers would be a GoodThing<tm>
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."