Points primary serve as a reputation system of sorts -- they provide a good general understanding of each user's experience on the site and also their knowledge of Pokemon. But their main practicality lies in our extra privileges system, which awards users with extra abilities, such as voting or flagging, based on their points. Most extra privileges can be earned by reaching 100 points in any given section, but you can also earn powers such as the ability to edit other user's posts if you gain a substantial amount of points.
If you are curious as to how you can earn points, the thread here provides a clear explanation of them.