Nintendo has announced that multiple social media related features will be discontinued from the Wii U and 3DS on October 25th, 2022. Starting then, it will no longer be possible to link a Facebook or Twitter account to a Nintendo account, sign-in to a Nintendo Account using Facebook or Twitter, or use any of the currently available image sharing services on either last-gen platform.
I would never use Twitter or Facebook as the authentication mechanism for any site.
Agreed. Terrible idea. Just create unique account logins for all of your services, and keep track of them with a good password manager. This is the way.
Fading further into the dark abyss.