I drew the same conclusion when first trying ScribusGenerator. It can be used in multiple levels of abstraction where the VAR table in csv can hold links to large text blocks held in backend database. Thus custom documents can be created "on the fly". Can also link to GoogleSheets through Python API.
There is another approach I tried. It is to use VAR notation to embed PHP snippets and the document (as XML with PHP clips embedded by ScribusGenerator) is then parsed in PHP server, to spit out XML>SLA file.