That’s how to run a Python script in terminal or CMD. It’s a very straightforward process, but it’s extremely handy if you ever want to quickly carry out a bespoke task.

So, for instance, you can remotely log in to another PC over SSH, open up a screen session, and keep your applications running there in a screen session even after you disconnect.

Normally, when created, they don’t use the underlying Python installation’s site packages directory. Apps that run in the venv can only “see” packages installed to the venv.