One interesting use of this coin could be using it as a way to pay mangaka directly instead of buying their stuff through a middleman publisher.
You can't buy a manga directly from the mangaka if he/she is working for the publishing company and/or once he/she has licensed all publication of his/her work to a publishing company. It's a matter of law. Also, no mangaka would do something as stupid as compete against the company making him/her money.