Well the nice thing is you can, Notebook is just a file format; but many tools allow you to select a bunch of text or use comments as delimiter and still execute using Jupyter. JupyterLab text editor does that by default. ANd I've seen vim plugins for that.

Notebook document are _meant_ to keep output as they are design for research and where the records of your results are important, but you also don't have to use ipynbformat with the notebook UI either.