KDDI au wallet

https://www.au.com/content/dam/au-com/english/auwallet/pdf/Chinese.pdf

au WALLET cards are cards for au users that they can freely use anytime anywhere. au WALLET cards will change your shopping experience by making it more convenient and allowing you to save more by using points. Don't miss out on the benefits!

WALLET Point is the point that you earn for the amount of money you use with au mobile phones and au Hikari.
Furthermore, by using au WALLET Prepaid card or au WALLET Credit card, you can earn points on everyday shopping.
Also, points can be used in various ways right away. You can use your points to charge au WALLET Card or exchange your points for products.
Earn points


Earn WALLET points by using au services and specified apps. Earn extra WALLET points by paying for your usual shopping with an au WALLET Prepaid Card or au WALLET Credit Card.

Use points

Use points on your monthly au usage fees. 
You can also use points for Data Charges to purchase additional data amounts in real time. 
One point equals ¥1.

Use points in many other ways

https://www.au.com/english/auwallet/