Kovid, When a colleague asks if I could send them such and such paper in say LIT it would be
nice to know that when I created the EPUB (my target format) in July last year from a DOCX (my most common input format) that I used book specific settings
Its only occasionally I need to do that, most often because the original was a PDF that I had to convert
and translate.
How would I know which settings I changed for the book? The 'book' contents would probably give me enough clues, but I keep timestamped screen shots of 'important' preferences settings such as conversions, so I could eyeball compare if necessary.
If I could
easily determine which of my existing books have specific settings then I would tag the books with 'special convert' and set a column icon (fat yellow C) if the tag was present. I guess its in the data column of the conversions options table - but that's a blob.
Its a just a
nice to have 
BR