Yeah I agree with you here. I was amazed he was able to make a RxJS look a like in such few lines of code using async iterables. It looks like a really nice addition to the language for those who already love FRP concepts.
Streams can be implemented with functions as well, no need for async generators. See `flyd` or `mithril-stream`...
I also do think JavaScript fatigue is real though I so I agree with the top level comment too, but I think it's more due to the tooling overhead.