This may seem like a good idea, but it gets problematic since you need to always use isinstance checks. Its actually discouraged to return union types by the mypy team: https://github.com/python/mypy/issues/1693
I think docker is great for providing isolated environment, venv has similar goals. pip-tools + docker is powerful combination, but the article doesnt mention pip-tools for some reason.
I tried to search for "cheese without holes" on Google and it yielded good results. I think the problem here is that the query is something people would rarely search.
I dont think list comprehensions are used to improve performance. One reason to use them is to improve readability, as the execution doesnt jump around with continue/break etc.
I get your point, but i think the main reason for using 80 character line length nowadays is that its more readable. Books use often line lenght of about 60 characters for this reason.
I think reviewing all code in the dependencies is not reasonable. When i add new dependency to my projects i evaluate how trustworthy the maintainers seem.
Its more like an alternative to scripts generating configuration from templates. they claim that this is better because you cant for example write an infinite loop ruining the script.