Jupiter is excellent at what it is designed for. For example, my usual workflow is as follows: when I develop a tool or model, I do so in a plain Python file. I then import the file from the notebook to create figures, demonstrations, documentation and so on, resulting in an immediate document that my colleagues and I can easily use for discussion. It's as simple and effective as that. It is also a great tool for teaching coding to beginners. Of course, notebooks are not designed for code development. Also, nowadays, if you want to, you can open notebooks in dedicated apps.