The short wheelbase on a tractor would make it difficult to achieve the same results as a motor grader. The long wheelbase on a grader will let the front tires travel over a fairly large bump or dip without changing the height of the blade much. The long distance between the blade and the front tires on a grader will give you time to change the height of the blade when you see a dip or coming.
When the front tires on a short wheelbase tractor travel over a bump or dip, the blade would rise or fall about the same amount. When the front tires on a tractor went over a bump or dip, the blade would be over it before you could react.
For rough work, the belly blade would be ok, but not for finish work.
When finish blading with a grader, we get down to the hundreth of a foot. Sometimes just scraping the blue paint off the top of a hub stake.