Let me take a shot at why it's important.
We spend years peering at code hunting for tiny, miniscule mistakes. Thus we're training ourselves, quite rigorously, to spot minor deviations.
We're also irrational in the moment: our aesthetic sense is bothered by certain patterns, and our social sense wants to assign blame for this "wrongness" to individuals.
An auto-formatter removes a ton of deviations that don't matter, and desocializes the aesthetics.
This saves code reviewers time and stress and helps them focus on what actually matters in the code.
And it only has to save more time than it takes to run "pipenv run black" to be measurably worth it.
(Showing up in an HN thread is a neat little milestone for my blog and me. Thanks for sharing!)
I'm no longer using it for Python projects.
It would be nice if pip could act more as a base tool and pass information back to a wrapper.
I like it because I can document most maintenance tasks as "pipenv sync && pipenv run X" and they Just Work with exactly the library versions specified for that commit.
But definitely look into poetry if you're packaging a library.
Whenever I have time I want to migrate all my pipenv projects to poetry.
The Python community is victim to pipenv's creator's marketing and shoehorning, that's why.