It’s already played by “just Twitch chat,” in the sense that the streamer doesn’t have to do anything to actively run it (I’ve seen someone put it on for their viewers while they were taking a break from the stream, if that is what you meant).
It might be tricky to run in the background while something else is happening on stream, because it takes up the full screen and would be hard to play if it were shrunk down much. It has some fairly small UI elements.