It's true that the audio, video, and data are all encrypted. But it's not the case that you can send audio and video over the data channel. Well, you could send audio and video data, but there's no way to pipe audio and video data into the data channel. That's an interesting idea, but it would probably take a long time to figure out and become part of the standard, if it ever happened at all. We'd probably need a worthwhile use case to justify it.