Piracy: ꜱᴀɪʟ ᴛʜᴇ ʜɪɢʜ ꜱᴇᴀꜱ

Almost. The technical stuff is going to be a bit butched, but I'll drop the legal speak and be more human for a minute:

What makes this unique isn't that Nintendo is going after them for providing the keys, but for actually using them. Yuzu asks the user to dump or acquire prod.keys on their own, and then it uses that to read encrypted data. The fact that it does that, regardless of whether the keys were obtained legitimately or not, is where the argument that it's a DRM circumvention tool lays. Yuzu itself is supposedly "circumventing" Nintendo's DRM process by using the keys in a way that bypasses all of the protections that Nintendo put into place to prevent the games from being loaded on non-Switch hardware.

The Yuzu devs' willingness to have FAQs and a quick start guide explaining the requirements and steps to emulate commercial games on Yuzu is definitely going to bite them and undermine any defense they had for not knowingly marketing it as a circumvention tool. Another criterion is that Yuzu has to have some commercial significance if it were to lose its ability to circumvent DRM. And, as we know, it's an emulator...

The best chances they have is to convince the judge that Yuzu isn't primarily designed as a circumvention tool (which, once again, isn't helped by their guide on how to run commercial games) or that it falls under the accessibility exemption added recently.