It's certainly not going to be counted against you if you have no significant hardship put on your app. I think it's just a way for adcom to assess the performance of certain applicants who may or may not have lower stats in light of the hardships they've experienced. Like a dip in gpa in a semester because a family member died, etc. You should not feel obligated to write something just to fill up space if the question does not apply to you.