Source: my current and previous job were basically data viz programming jobs which were all about optimizing said iterative loop for scientists. Going from minute-long to sub-second rendering speeds is a game-changer for many.

EDIT: having said that, this kind of reminds me of what the biggest difference between analog and digital photography is for me, namely whether or not you get instant feedback. I do remember from my art school days that in my experience film was a much better option for training the skill of observation and composition than digital, because it forces you to essentially picture the photograph before you take it. However, once you get somewhat decent at that... I'd switch to digital and reap all the benefits it has ;). The same logic might apply to learning how to plot your data.