Average-weighted tests can go die in a ditch
It just discourages cooperation leading up the the exam, because you actively benefit from your peers performing worse
it works when tests are graded where the intended score is not 100%. having a test basically be “not finished” shows which subjects on a test was not properly gone over, thus the curve would apply and remove said question from the exam. if it were to be graded in a 100% scale, the question would exist to not give the class a perfect score regardless.