Appeal pertains to the overall physical aspect of someones looks. In other words, their SMV. There are objective aspects when it comes to determining SMV like ones facial rating however someones preference on height, body, etc, is a subjective desire regarding YOUR type.
PSL and appeal go hand in hand because psl is a determining factor in someones "appeal." A misconception is that appeal represents the more "feminine-esque" or a less uncanny person but thats really just being less dimorphic/angular; at that point it becomes subjective because whilst obviously theres an ideal, people can choose what their personal preference on how they prefer their men.