Ah, I hadn't heard about that API. But audio/video encoding and streaming was a basic use case from launch. I guess the new API lets you handle the encoded data yourself, and not necessarily send it out over WebRTC.
MediaRecorder is essential for video encoding. A friend of me had to implement video encoding in JavaScript when he tried out uploading videos to the server. He did something like this: write a video frame to a canvas element, then encode it in JPG and upload that JPG to the server and then make a video out of the JPG frames. Absolutely ludicrous.
