points debit / tokens credit

Has anyone used the after sales points debit / tokens credit sections in products? I would like to create a points system for customers. IE purchase this product, receive 100 points. Then use those 100 points towards future purchases. It seems like that is what this section can be used for, but am having difficulty finding any documentation on it's usage and how to set up. The online help only goes so far. 

Thanks
TJ