There are two main reasons why someone may actually need a GoPro:
1) They need the fisheye lens to capture the subject while being very close. For example, you want to capture your entire body while skydiving. Or you're a surfer and the camera can only be 2' away. Or maybe you're a pilot and, again, the camera can only be 2' feet away. Or maybe you need something very light to be mounted onto a helmet. Problem is that the lens creates a huge amount of distortion making the GoPro a very poor choice for general videos.
2) You need a small and waterproof camera because a normal camcorder would either be too large or too heavy, or would likely get damaged (e.g. water damage).
A GoPro is perfect for these situations because of its fisheye lens, it's light weight and water proof.
If your needs are either one of these two reasons, or both, then you probably need a GoPro. Otherwise you should not buy one. Most people who don't have either of these two needs who do buy a GoPro hate it because of the huge amount of wide-angle distortion created by the lens.