[lonelappde]

You're not wrong, but Jupyter is terrible for everything about programming except in-document HTML/SVG visualizations of expressions (no support for unit testing, laggy Ui response to user input, broken Undo/Redo that throws away data, buggy browser based text editing), yet that one thing is worth all the suffering, so we'll take any improvement we can get.

I don't understand why VisualStudio doesn't have LightTable like expression playground yet, but until it does, Jupyter is what we have -- a fancy REPL and document publishing format being abused as an IDE.