@martincigan You mean as a kind of magic math that always works? Maybe, but then the person who presents such a figure needs to explain why they believe so. I am pretty sure the reason is simply that this is the easiest function to fit.

Pro tip: If you want to expose a #datascientist for not being a #statistician, (and you could do this here too), ask them: What precisely do these shaded areas around your curves represent? Stammering guaranteed.