it seems the 'advantage' is to allow non sql access to the files, as well as non transactional access to the file: "the special thing is that you can access these files and directories from windows applications as if they were stored in the file system."
then the question is why would you bother using sql sever to manage this. i guess so that you can back it up with all of your other sql server data as well as provide access to it via sql.
It seems that powerbuilder could access the files either via blob processing or via the file system