The issue with scanning documents into a db is that it tends to bloat the db, meaning your db becomes larger than it need be with what is unsearchable static data. backups become trickier, especially if you start crossing the threshold for DVD RW. The jury is out on how reliable a means of long term storage DVD RW is.
The advantage is that the data is held inside the db so there is less risk of soemone altering the data outside the system
many propel advocate storign a URL to thescan inside the db (along with other pertinent data. the advantages:-
well you are not consuming space in the db, it can be trickier (assuming set up correctly) to delete data backups are easier as (assuming you are using incremental backups previously backed up data doesn't need to be archived over and over again
what I have done int he past is scan documents into an open directory, then move the documents to a restricted access directory that users can read, but not write or delete
however that is not a pure db solution, the network needs to be effectively setup, a batch process needs to periodically clear out any files from the public area to the restricted area.
last major project I worked on used WORM drives for added security (whether it was real security or pretend security was a moot process, however it ticked boxes for the auditors who demanded it.
I'd rather be riding on the Tiger 800 or the Norton