From experience, I think the whole "human-readable" idea is a bit overrated. All it means is that the format is entirely/mostly in ASCII. But if you have a hex editor, like all good programmers should, binary formats are not any less human-readable (or writable) nor more difficult to work with; and for some, even a text editor with CP437 or some other distinctive SBCS will suffice after a while. It's somewhat like learning a language; and if you are the one developing the format, it's a language that you create.

Then again, I grew up working with computers at a time when writing entire apps in Asm/machine language was pretty normal as well as other things which would be considered horribly impossible by many developers of the newer generation, and can mentally assemble/disassemble x86 to/from ASCII, so my perspective may be skewed... just a tiny little bit. ;-)