The video quite definitely states otherwise for most benchmarks. Only a few benches still show regressions over P2, and according to Victor they're unlikely to affect the vast majority of systems.
So, just largest and more important part of Python's non-hobbyist users?
Like tensorflow - https://github.com/tensorflow/tensorflow/issues/1
I've just installed it using conda in Python 3.6 just fine.
I don't really remember all that clearly, but my recollection is that numerous caveats were made fairly clear (like the new IO not being optimized and so on). I guess something needed to go out the door but I wonder if the biggest mistake was calling that release the 3.0 release (rather than something that would have better tempered naive expectations).