An observable is definitely not a stream of promises, because an observable is push-based, while a stream of promises would be pull-based. Big difference in pe

An observable is definitely not a stream of promises, because an observable is push-based, while a stream of promises would be pull-based. Big difference in performance, implementation and what operations are possible or not. Even if you add back-pressure in that protocol, it's still a big difference. And yes, my point is that an observable is close to being a sort of superset of a promise, but not close enough.