What advantage does this solution have over having a custom font configuration on Linux with fallback support for a font with unique unicode glyph support? In my case, I have Google's Noto font as my main font and have Font Awesome and Emoji One as my fallback fonts and it seems to cover everything.
I totally agree that fallback is the way to go. Unfortunately I couldn't get powerline glyphs to work on my archlinux box, lost patience and just grabbed the droid patched fonts.
I would say that it adds portability, consistency and makes it easier to have glyphs working straight.
I'm genuinely curious, do you have any idea how other OSs handle fonts? Does OSX have something similar to Linux's X11's font configuration? What about Windows?
What exactly do these patched fonts do or add?