You have not described the context in which the question arises, so this will briefly discuss grading systems in general.
A grading system can have a large or small scope. A grading system with small scope might the be the one that assigns a keep/don't keep grade to leftovers in your refrigerator.
A grading system with large scope is the one used for students in schools. The A-F grading is not only used to assign homework and test grades, it is used for attendance, contribution to class discussion, and more. It has implications for educational opportunities offered, scholarships, job opportunities. One test grade can have effects more than 25 years later, long after life, career, and family have tested the person in far more meaningful ways.
All grading systems have limitations. Chief among them is the possibility of incorrect assignment of grade. In many cases, a slight error is not significant, but it some cases (grading food in your refrigerator, for example) it can cause illness or death. Another limitation is that grades may be assumed to have meaning that they do not have. School grades, for example are often assumed to say something about the ability and character of the person. They do not. They only reflect the judgment of the grader in very specific circumstances that usually have little relation to life.
A grading system can have a large or small scope. A grading system with small scope might the be the one that assigns a keep/don't keep grade to leftovers in your refrigerator.
A grading system with large scope is the one used for students in schools. The A-F grading is not only used to assign homework and test grades, it is used for attendance, contribution to class discussion, and more. It has implications for educational opportunities offered, scholarships, job opportunities. One test grade can have effects more than 25 years later, long after life, career, and family have tested the person in far more meaningful ways.
All grading systems have limitations. Chief among them is the possibility of incorrect assignment of grade. In many cases, a slight error is not significant, but it some cases (grading food in your refrigerator, for example) it can cause illness or death. Another limitation is that grades may be assumed to have meaning that they do not have. School grades, for example are often assumed to say something about the ability and character of the person. They do not. They only reflect the judgment of the grader in very specific circumstances that usually have little relation to life.