Curious that they discuss several options, but ignore the totally obvious one: just use jupytext [0]. Jupytext is a (tiny) jupyter extension that reads/writes notebooks as python files, with text cells being represented as comments. With jupytext, you do away with the stupid .ipynb format. As long as you don't need to save the cell outputs, which is the case for version control, jupytext is the way to go.
People: pip install jupytext. All your python files will become notebooks, and your notebooks will become python files.
People: pip install jupytext. All your python files will become notebooks, and your notebooks will become python files.
[0] https://jupytext.readthedocs.io/en/latest/