It's not a "test", it's an "assignment". Assignment is a way to practice what you've learned, and a (good) teacher would want to get your original thoughts so they could adjust their instruction and teaching material to what they believe you missed in order to improve your mental model around the topic (or in other words, to teach you something).

Perhaps the problem is that they are "graded", but this is to motivate the student, and runs against the age-old problem of gamification.