I want to go study at the University of Auckland or Victoria University, do I need an endorsement?
Some university courses have competitive entry, where you need to have a certain amount of credits with Merit or Excellence. University of Auckland does this in particular, where you need a certain rank score to get into some of their more competitive courses. The rank score is calculated by counting your best 80 credits, and Merit and Excellence credits give you more points and a higher rank score. However there is usually no need for a certain endorsement.
That being said, having Merit or Excellence endorsements can lead to gaining scholarship money for university study and are also an achievement in and of themselves. Having worked hard for an endorsement also means you are likely to be better prepared for university study.