It's handling of soft-hyphens is standard, standard HTML that predates ePub.
I'm not using soft hyphens. I do use them sometimes in websites, there I use a bullet in the source so I can read the page and see where they are and the use a php wrapper to preg_replace them with the actual glyph when served, so that view source is readable. Can't really do that in ePub and several entities in words is just horrible to work with in a text editor.
-=-
http://unicodefractions.com/
I'm curious as to how many devices have built-in glyphs for those commonly used fractions?
I'm guessing some have them but I'm also guessing many don't. There's really know way to know, hence why I want to embed fonts.
I suppose for authors who never use fractions maybe that doesn't matter, but the artist drawn glyphs really do look better than using n/m.