Not so much for maps, but I've learned that many fonts are perfectly usable in print publications, but for electronic publications like PDF format, many fonts are not allowed to be used as such. In electronic form, a given font embedded in a PDF file contains all the possible glyphs within a font set. Think of a font as a software package, when embedded into a PDF the use of a font includes everything, not just the letters you used of a given font in a publication. So depending on if you convert to outline graphics within a map, a digital only PDF map contains all aspects of a given font, and may not be usable for distribution. Something to have some concern about when using fonts in maps.