One can come up with several reasons to store your Oracle Reports output. Especially in cases where it needed to prove to authorities that the document you delivered was not manipulated by the end user.
Consider a pharmaceutical customer, they will need to apply to FDA regulation 21CFR11. Or perhaps even better, to prove some end user did manipulate the document.
The following document describes two options to store an Oracle Report as a Blob in the database.
The first requires only PL/SQL the second option uses the Oracle Pluggable destination functionality available from OracleAS Reports Server 9i and requires the pluggable destination Jar file.