The thing that I find really daunting with Jupyter is the set of APIs that it seems I need to learn in order to get it to do anything cool, like for example visualizing data or a function, or making an interactive widget that does the same. I don’t remember the same kind of pain when playing around with Mathematica. I really want to like it and learn it — I really like interactive programming. It just never makes it high enough on my brain space list to seem worth it.
Since C# is my daily language, this is pretty cool though. I just really wish that I had a use-case strong enough for it to overcome the initial pains of learning it and the ongoing mental maintenance of staying usefully fluent in yet another set of libraries.