It allows making custom profiles for games for the On-Screen-Display. It is good if some games you want the OSD to be in one corner but in Game B you want it eslewhere. It also is for some games that detect the way it displays the OSD as a "hack" so you can change how it gets displayed (Application detection level). You can also customize the color/size of the OSD in that.
If you don't need the OSD then you'll be fine without it. I use it to monitor Frame-rate/GPU temp in-games, it can also show time, GPU use, PCB temp and more.