Having more points, properly developed in well-structured paragraphs, generally gives you a better chance that at least some of what you have written receives points. Literature is very subjective, and you can never know exactly what the examiner will be looking for; having more points improves the chances that at least some of the thigns you write matches the examiner's criteria. Furthermore, if you only develop a few points, you are running the risk of getting bogged down with some of them and distracting yourself from what the essay question is actually asking.