When I was a graduate student at Chicago, Milton Friedman was rumored to have given a presentation on how to write a doctoral dissertation in which he said something like:
Take everything nonessential, and move it into footnotes. Then collect all the footnotes into an appendix. Finally, delete the appendix.
My memory is that Deirdra McCloskey, in her wonderful advice on how to write economics clearly, also advises against footnotes. I at least attribute this advice to McCloskey (and Friedman) when I pass it on to students.
But sometimes, when I write an article, a misguided referee, or editor, insists that I omit some stuff that I think is really good. When that happens, sometimes, if I feel strongly, I sneak some of that material back into the paper in footnotes. Maybe no one will ever read it, but I feel better that it is still there.
And every once in awhile, it may turn out that the footnotes are what matter most:
It was typical of Schumpeter’s love for theory that he rejected Marshall’s view that the reader could skip the footnotes and appendixes. If time were short, Schumpeter advised, read them and skip the text! (p. 7; italics in original.)
In this case, though, I suspect that Marshall was right, and Schumpeter wrong.
Samuelson, Paul. "Compete as an Economic Theorist." In Schumpeterian Economics, edited by Helmut Frisch, New York: Praeger Publishers, 1981, pp. 1-27.