This is a product I REALLY want. Since I want to be able to diagram entire complex systems without always seeing 10,000 boxes on screen. You could start a presentation at 35,000 feet, showing the entire rough structure, then zoom into different regions where more detail will appear (infinitely)
Nestable feels more like excalidraw, with a folder/file structure?
I used to make entire presentations, systems diagrams, story boards, etc all using scale as a meaningful piece of information. You could go way overboard with it but it was really great. (We used to have a saying "Your Prezi is making me dizzy" for folks that overdid the flying nature)
[1] Like with all modeling, there are of course assumptions and approximations. Different techniques have different strengths and limits. Still, these are all well vetted, studied and used by people who care about accuracy.