That natural minor is incorrect; it's missing the 3rd degree. It could be argued that the melodic minor is only correct when ascending, but I suppose I'm just being nit-picky.

I can see how this makes someone comfortable playing scales on the piano, but I'm not sure how this teaches someone the circle of fifths. I'm probably only saying this because I know it already, but I think learning the circle of fifths is easier without an instrument in front of you, instead of trying to find a way to use the instrument as a vehicle to learn it. Applying it to an instrument becomes easier when you know it in your head first.