If you measure it less, you'll have a weaker argument for how the education system is doing!
Your comment is precisely the problem: objective metrics will always support their proponents' arguments for more measurement, while any upsides to a lessened objective grading will be difficult to show because they'll involve subjective assessment or less assessment.
Do not confuse the investigator's convenience in accessing a truth value for the truth value itself.
That argument has been made many times and in great detail. See for instance the work of Diane Ravitch, former US Assistant Secretary of Education (https://en.m.wikipedia.org/wiki/Diane_Ravitch)
