Just last week, on Tuesday, February 26th, 2024, news broke out about the Yuzu emulator team being sued by none other than Nintendo themselves, with Nintendo claiming that the emulator apparently allowed users to play certain games early (due to street dates being broken) and also allowing...
The emulator itself doesn’t necessarily have to exist only to run retail games. It could be used to develop or debug homebrew and marketed as such. They wouldn’t even need to have decrypted the operating system to understand it, as Atmosphère is a complete reimplementation untainted by Nintendo code.
If it ran retail games as a consequence of being accurate to real hardware, that would just be a happy accident. And as long as the developers don’t acknowledge running retail games and don’t directly assist in fixing them, they have plausible deniability.
I’m a big fan of the “buy a game and crack it right after” philosophy. Respect property rights until something is in one’s legitimate possession, and then remove any encumbrances preventing it from being used in the way the purchaser wanted.