> FRP streams go beyond promises by allowing many returned values. This is pretty nice, and shows how FRP is at least as powerful as Promises.

The fact that you can only return a single value from a promise is a feature, not a limitation. In synchronous code, you can only return once from a function. In asynchronous promise code, you can only fulfill the promise once. There's a parallel.

If you want to "allow many returned values" you can just use a callback. You hardly need a "stream" for that.