Perfect for complex dialogs with loops, backtracks, and multiple endings.
The processing nodes are a good idea and bring a lot of possibilities.
What’s cool is that you feel you can take a lot of freedom: the HTML export is light and simply hackable if you want to change the style or something, the JSON export is simple enough to be used in another game engine with a few adaptations. I think you could go even further in this direction, find import and export options that allow the tool to be even more versatile and suitable for many different uses.
Nice tool overall ! (And the programming puzzle was fun.)