As far as I know, you can write and execute codes in the browser and it is based on Python. What's so great about it? I can simply write and execute Python programs in my editor.
That's true. The Jupyter notebook does not offer more functionality than "normal" code.
However, it is really structured like a notebook. So it's extremely useful to explain or experiment with something.
With this tool you can easily assemble presentations and scientific documents. For the actual target group, which limits their programming to rather small, mathematical scripts, this is an optimal interface. Different media content (videos, text, images, diagrams, etc.) can be quickly and easily combined in one document.
In addition, the data can be easily split (they are saved as JSON) and converted into other formats (such as LaTeX or PDF).