I largely agree with you... but then I wonder "how does this deal with recursion, or even repetition", and it turns out it doesn't: it could, I see how it could and it even seems obvious how it could, but because it seems to be trapped in the paradigm of a text editor it simply doesn't handle these cases well, which means that for anything other than simple code you lose this superpower: even at the end of the demo, you see the usage of map means the list-item rendering kept getting its values overwritten by later calls. Frankly, I think this tool is trying to poorly emulate a REPL combined with a debugger in the context of a text editor: you need to see the state of not just the first or last list-item call, but all of the list-item calls. This is then probably why people are somewhat unexcited: while more work, adding a log statement to list-item and getting a trace of the full dynamic execution is actually more valuable and provides better introspection than adding a call to the function in the source code on the left (which is frankly unnatural in the text editor context anyway) and then seeing values displayed inline with the static code on the right. So, maybe they will change their direction in a later release, but this just isn't doing it for me yet.