"NEW: Nintendo is suing the creators of popular Switch emulator Yuzu, saying their tech illegally circumvents Nintendo's software encryption and facilitates piracy.
Seeks damages for alleged violations and a shutdown of the emulator.
Notes 1 million copies of Tears of the Kingdom downloaded prior to game's release; says Yuzu's Patreon support doubled during that time. Basically arguing that that is proof that Yuzu's business model helps piracy flourish."
You can download and view the latest Yuzu source code for free and do practically whatever you want with it (GPLv3), including building and running it.
What paying via Patreon provides you is access to early access builds of the software. You're paying for the convenience of them compiling the latest version of the software for you.