Many comments are comparing Glamorous Toolkit to a JuPyteR notebook. It's worth noting that the comparison falls short because Glamorous Toolkit itself, including all of the UI [1], is implemented in the target language.
The graphical part is one source of difference, but there others as well. For example, chapter 4 in the Rewilding Software Engineering that Simon Wardley and I are writing compares what we call defined explorations (as seen in Jupyter notebooks) with dynamic explorations (as experienced in Glamorous Toolkit): https://medium.com/feenk/rewilding-software-engineering-a360...
(I looked, but couldn't find that in the documentation)
Will keep working with and experimenting with it.
A single tool in the toolkit is already equivalent to notebooks, at least from what I glimpsed at the introductory video. Then you have the rest of the tools, how it can easily inspect the objects, and probably manipulate them.
This is probably one of the future ways in which we will work in programming in the future, when someone creates some similar tool, around a mainstream language, that can easily interact with LLMs, APIs, and data visualization tools.
In fact, there is already LLM integration including programmable chats with the possibility of contextualizing the interface of each message in the chat :)