The biggest benefit, which I haven't found much of a practical need for, is you can continue to emit 1...n times, whereas a Promise only resolves once. Since it

The biggest benefit, which I haven't found much of a practical need for, is you can continue to emit 1...n times, whereas a Promise only resolves once. Since it's an indeterminate number of times, you need to subscribe and unsubscribe to prevent memory leaks, so it just adds more overhead. Use a Promise if you only need to resolve once.