> There is already a mechanism to validate the settings.py file inside django.

It's not exposed, but it's very limited.

> The different context stuff can be handled by using env vars, and a nice python wrapper, like python-decouple.

It's just one of the way to do it. Go to a new project, they use a different way. The main benefit of Django is the fact that a Django project is well integrated, and you find similar conventions and structure from project to project, allowing to reuse the skill you learned and build an ecosystem of pluggable app.

Just so we're on the same page, this is the validation I was referring to -

https://docs.djangoproject.com/en/2.1/topics/checks/

Standardization is always an issue, I guess. Env vars seem to be the norm in the community in my experience, whatever that's worth..

Ah the stuff used for the password ?

I would be more of a fan of something like marshmallow, checking the whole thing.