You enjoy the knowledge you have gained by using eNotes! You could also use them for bragging rights if you have friends on eNotes who don't have as many as you do!
There isn't anything specific to "do" with eNotes points. They are an indication of how often a given person is involved with eNotes and can be a reflection of the kinds of activities someone does most frequently while on this website. More points are awarded for some kinds of activities than for others. Someone who is an eNotes editor and spends lots of time answering questions like yours will accumulate notes faster than a student who submits a question occasionally. There are lots of ways to earn points - check out the link.
no use of earning points. you cannot exchange it for money or purchases.
Aww... I thought we can change the points as real money or something. Oh well... I guess i'll just keep it for fun!!! (: