Sure, even the basic math courses like calculus are cumulative... no wonder this course is cumulative. Although I don't like it going over what I even don't remember at the end of a semester, I think it helps in the long run because you may end up understanding the whole course thoroughly and feel like you really learnt something. Let's go for the cumulative final!
Most courses always tend to have the last part of the content on the final since they haven't given an offical exam for that content yet. I have had one class where the final exam was only on the material covered after the second exam in the class, and it helped to be able to concentrate on that area to study then many as opposed to cumulative exams. So in my opinion it helps when it comes to studying especally if you have alot of exams that week.