A couple of issues with that - first as you can see your node point that you have pulled up is above the surface and hence can not be relied upon for an accurate height. Second contours and spot heights arent always as even as that and usually curve about on plan which causes problems with moi. It is possible to create some sort of network grid but it is a bit of a pain and not very user friendly. Another problem is when you need to add in straight lined contours which don't play nice with curved ones as the loft can distort the surface.

Thanks for trying though.