Emacs will sometimes become slower (especially remote emacs), but it will always buffer your keypresses and do them in the correct order.
Jupyter (for whatever reason), doesn't do this with the result that I ended up wanting to create a new code block, but that keypress got lost and then i end up ruining my original code block.
I 100% noticed the difference, and it was super frustrating (fortunately I left that job, and have managed to avoid Jupyter in the new gig).