Above/Bellow only test for bigger/smaller than, not equality. How would you test if a variable has a value bigger or equal using above? If we assume the value n is an integer you could test n-1, but what if n is a float?
Example: How can we test if a variable is bigger or equal to 9.8 using above?
Same thing for bellow. I agree that if above/bellow also tested equality min/max would not be needed.