The point is not just Django because you have all the other dependencies as well. Docker can also replace the need for a virtualenv altogether (e.g. see https://realpython.com/blog/python/django-development-with-docker-compose-and-machine/
). Plus you missed my point about production vs. deployment. Local development never
works exactly the same as on the server (this is a well-known problem and one of the motivations that the developers of Docker understood).
And yes, I have always used virtualenvs in the past; no doubt they are useful when you want to work on different Python projects; especially if they are small standalone ones.
Anyway, point was not to start a "virualenv vs, Docker" debate - just to point out that Docker is useful for readily deploying any kind of tool or service and is being adopted by DevOps teams for that reason. It may not be useful for your specific use case; but those working in production its becoming a "must have".