Technology

Nintendo had games breaking at parts because of interrupted services, even games that are single-player or playable offline.

Some examples :

Fire Emblem : Shadow Dragon has a shop that connects to the internet and is the only place where you can get an item required for a specific class promotion. I shit you not, the only reason it needs access to a long dead server is to check the current date, because the shop's content depends on the day of the month.

Similarly, Metroid Prime 3 and Metroid Prime Trilogy had an "online" component... Some of the in-game rewards could only be obtained by spending "friend credits". What happened is you earned a credit, you couldn't spend it yourself, you had to send it to a friend and have them do the same for you. This was the only way the games used the online service. Bonus, they rereleased Trilogy on Wii U, long after the server shutdown, and did not do anything to let you go around that.

And also on the Wii U, Mario Vs Donkey Kong Tipping Stars had a level designer. You could unlock parts for the designer with stars, earned by playing levels... Shared on miiverse. They shut down Miiverse, even before the end of the console's (short) life, and they even kept selling the game after that, with only a short message to warn "not all functionalities" were available. The truth is that without the miiverse stars you could barely unlock anything for the designer, so it was basically useless even for offline.