After the service ends, it will no longer be possible to purchase downloadable software or additional content for the 3DS and Wii U through the Nintendo eShop. Therefore, users should take this last chance, as it will be the last opportunity to do so.
Wii U
It should be noted that the charging service from 3DS/Wii U to the Nintendo eShop ended on August 30, 2022, but by linking your Nintendo Network ID to your Nintendo Account, you can still purchase 3DS/Wii U downloadable software and additional content from the Nintendo Switch, PC, smartphones, and other devices.
Source: GAME Watch
Contributed by nado