If you want to store markdown in your database but you want to user to use a basic wysiwig/content editable editor it can allow you to not go through the full blown markdown editor.
Similarly for sanitization, if you want to really reduce the subset of allowed tags, and to normalize input it's a pretty good intermediate format. Did this for a classified ads site, that included listings from external companies... it was easy enough to shift H1-H3 to H4-H6, keep basic formatting elements and eliminate the rest.
Markdown in the database is also easier to look at, reason with and takes up a lot less space. Especially if the content was pasted from say MS-Word to a Content-Editable field... omg the level of chaos there.
Markdown in the database is also easier to look at, reason with and takes up a lot less space. Especially if the content was pasted from say MS-Word to a Content-Editable field... omg the level of chaos there.