> Markdown is a really poor storage format. There is quasi-official standard (CommonMark), but since it's feature-poor, people mostly use something else, like GitHub Markdown. Individual apps often extend Markdown in various incompatible ways.
I hope GitHub and Obsidian are going to synchronise their MarkDown extensions in near future and this will become The Standard. Whatever a case, anybody can easily write a script to automatically convert any Markdown flavour to another.
> why should books be in Markdown? Markdown's biggest (or the only?) advantage compared to binary/XML based formats is sort-of readability in plain text, but that's just not that important for the majority of publishers and readers.
Read anywhere. I mean anywhere. Without a need for software as complex and resource-hungry as a web browser engine ePub would require. I used to read TXT books on a pocket MP3 player during the pre-Android era. Also very easy automated processing.
In fact my actual preferred format for books is FB2. I mostly convert ePub books to FB2 to read on a PocketBook eInk device because it would use book-specified fonts and pages (which I never want) if I don't and FB2 is sort-of Markdown-like (in terms of its logic and features) XML. FB2 also has a great metadata section to store information about the book.
And besides books there also are documets. Word/LibreOffice documents others would send me often are real pain to modify as WYSIWYG word processors bundle tons of redundant invisible formatting details for every bit of text even when not asked for.
“Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” ©