We all have one club in our bag that is horrid and we don’t even know why we carry it (putters don’t count 😀 ).
These clubs can serve a purpose. When you are working on something that you think is a miracle cure for your game, bring out Old Unfaithful and see if you hit that well.
For me, it’s any hybrid club. So I purposely have one in my bag to test out what I am working on.