Our Addiction To Grades
The adult world is addicted to grades. Subsequently, so is the child world. There is little else in formal education so firmly entrenched and supposedly irreplaceable as the A-F (but no E) system.
A few examples.
Many educators have stories to tell when the end of a grading period nears. Students begging for grades. Parents begging for grades. Parents offering major external incentives to children like money, technology, even cars for top grades. Plenty of crying, anger, even low-level threats in the teacher's classroom and principal's office.