That's xviii to you, buster!

I've just finished reading a manuscript that cites sources via endnotes marked with superscript Roman numerals, a text that looks as if it's been invaded by refugees from a remaindered algebra textbook. Endnotes are annoying enough, but when nearly every sentence is embedded with one or more tiny strings of xiv or xvi or xxxviii, I wonder who ever thought this was a good idea. What would compel a Citation Guru to prefer Roman numerals? For what problem are Roman numerals the solution?