The difference is that with a stream of websocket messages every so often you need to deal with the framing. With a stream of bytes you don't. This precludes the use case that was the basis of the argument for 63 byte messages if you ever have to 'stream' a 'message' that needs to be longer... Sure you can send it as multiple fragments but then you can't do the 'here's a file handle, read the stream' thing that was proposed.