So, from what I see, this takes the audio from your phone's Switch app and Switch console and you can adjust the volume. Or, you could probably just use any old microphone/headphone combo, like the one packed into every single smart phone and use that with the Switch app and have the audio feed separated from your tv instead, that's how I did it with PS4 anyway. This peripheral isn't necessary unless it's important to have game audio and chat audio into your headphones. So no sweat off my back.
I have a feeling any Bluetooth speaker or headphones you could connect to your phone and that feeds into the game as well.
Well find out in a two weeks for E3.