The question for me is whether the policy inflates the reported average scores of admitted students? It seems to me that if an applicant has a great score, they submit. If they don’t have a great score, they don’t submit. As a result, the reported average test scores end being higher than the actual average score of the class.
Yes, I think this is an ulterior motive that colleges consider when becoming test optional. Many test optional schools have very high average test scores that do not match up with their acceptance rates. This makes the schools seem more competitive than they really are.