Is it to let the teacher know that the student has internalized the matter?
That the student studied for the test?
To make sure if the student gets an accreditation, but in the end proves to be a dumbass, that the institution can prove they didn’t give the accreditation away for free?
To motivate the student to study, because there’s a test to pass?
Systems are made of input, checks/balances, output.
But, what do you do if you get at a point where no one knows what certain checks/balances are for anymore?