Nintendo is a bit of an odd company in which some of their ideas seem to be the product of forward thinking, but yet there have been some instances in which the company has been slow to adopt newer technology or features that its competitors have embraced, like the Wii Shop Channel which marked the first time that Nintendo embraced the digital game distribution method.
However given that the focus is currently on the Nintendo Switch, we guess all good things must come to an end as Nintendo has officially announced that the Wii Shop Channel will be shutting down in 2019, or to be more specific, it will be shutting down on the 31st of January, 2019. We suppose this still gives gamers a little over a year to adjust to things, but if you still plan to keep using the service, note that adding funds will only be allowed until the 27th of March, 2018.
This means that after that unless you have any funds remaining in your account, you won’t be able to purchase games for either the Wii or the Wii U via the Wii Shop Channel. Of course physical purchases will still be possible assuming you can still find copies of the game you want, but the digital distribution method will be coming to a close.