Jupyter is incredibly powerful. I think a lot of the surprise (which I also had) is when you come from compiled languages and see the huge difference between running a compiled machine code vs just some faux interpreter. Python doesn’t have that. Everything is an interpreter (in a very loose sense). Jupyter, ipython, the shell etc all typically work similarly. If you think the overhead of rendering a webpage should slow down Jupyter, that is not the case. The “kernel” running your code and what’s handling your interactivity with Jupyter are separate processes.