The Wii Shop Channel is closing for good in 2019 and users are no longer able to add points to the digital store. As of March 26, 2018, it is no longer possible to add points to the Wii Shop Channel using either a credit card or Nintendo Points Card. Any points added before that date can be used to purchase content on the Wii Shop Channel until January 30, 2019. The official announcement from Nintendo is as follows:
Reminder: Wii Shop closes January 30, 2019
Dear Nintendo fans,
As previously announced, the Wii Shop Channel will close for good on January 30, 2019. The ability to add Wii Points was removed earlier this year, but if you still have any Wii Points that you wish to spend, you must do so before January 30, 2019.
If you have any questions, please see our Q&A.
Please also note that as the Wii Shop Channel closure date approaches, remaining video-on-demand services on Wii will be ending as well.
Thank you for supporting Wii Shop Channel and for being such great fans of Nintendo.
Your Friends at Nintendo