don’t see the need for exit exam if every individual class
was tested and classes built upon each other.
We have universities and schools now that test every class pretty much. And you can see the results. Some of the snowflakes are dumber than a fencepost and half as useful.
A final, exit exam would ensure that they had adequately mastered the entirety of the material. Additionally, if someone could pass the final exam without taking all the classes, he or she would still be shown as having learned the material and thus graduated.