I wonder what kind of stuff you're working on, that this makes you 4x more productive. For my work (stream processing, analytics, in Clojure), it's useless, AFAICT.
This is not that surprising. There's just not enough source material for it to have learnt from and generalise.
I have a friend who does embedding programming in C++ - and he finds it occasionally useful but mostly it fails. He has the double whammy of being in a small niche and a lot of embedded people still writing in C (and doing it in very odd ways).
[Edited for clarity]
I think in general it's just really good at Python, so it's a boon if you code in Python. I was using it for Kotlin the other day and while it helps, it's not as immediately good in my experience.