This video is not worth 50 minutes. tl;dr: A bunch of stuff about typing that you probably already know and for which there are better resources. He cites a

This video is not worth 50 minutes. tl;dr: A bunch of stuff about typing that you probably already know and for which there are better resources. He cites a couple studies showing that static typing doesn't improve productivity. His own analysis of python projects on Github shows that only 3% of bugs are caused by type errors. He acknowledges that the evidence is not good and thinks that the industry should invest in doing better studies.