When you were in school and assignments/tests were passed out, you always were interested in how
other students performed on an exam.
You may have made, say... an 71 (out of 100). Well... is this good or bad?
So if the people around you made 50's; you felt pretty good. If they made 95's, well.. you didn't feel quite as confident.
You were then interested in what the class average was compared to your grade. And... how students in the university and students historically performed. Without some basis for comparison, it's really difficult to determine how you are performing.
Consider an old fashioned cobbler sitting at a bench making custom shoes and custom shoe laces. Instead of guessing every time how long the laces should be, the cobbler may put marks on the work bench, to measure each time so the laces are consistent.
To me, benchmarking is simply a relevant and valid standard for gauging performance.