When slating your own ideas on a certain subject, it is not unusual to take one side or the other. But in some cases it can occur that you have no particular opinion on the topic and therefore an argument arises in which you do not take sides and instead lay out the facts for the reader to decide which side he or she, if also undecided, will take. In the essays "The case for …
showed first 75 words of 941 total

showed last 75 words of 941 total
…is trying to pertain to them and will likely want to know more. The will get all the facts on the beetle, not just the negative or the positive, and will be more informed on the topic in general. You truly cannot say that one type of essay is better in the pro-con versus argument battle, but you can say that each have their own specific things that can help or not help the reader.