Of course there is a need for post-prep, it is designed to to a specific job.

VIM's HTML conversion is designed simply to convert the syntax coloured text to HTML format suitable for representing as a flat web page.

Post-prep is designed to convert plain text to a format suitable to posting to the KiXtart forums which might require fiddling with the code slightly to get it to look right and to get around the "tag not allowed" and similar posting problems.

Don't stop now!