What is the point in this exactly? FLAC is useful for selling lossless audio, so you'd be able to re-encode it into any other codec when needed. But to play something on-line (which browser support implies), you can as well use lossy codec like Opus at transparent bitrate, and save the traffic in the process.
That said, it surely doesn't hurt to have that support in the browser, I just don't see it being very useful.
That said, it surely doesn't hurt to have that support in the browser, I just don't see it being very useful.