Google doc converter can be used as an alternative technology to unoconv/libreoffice for the "any documents" to pdf conversion in the assignment annotation.
In many scenarios the unocon/libreoffice could'nt simply installed so gdoc converter it's a valid alternative.
BTW if someone is interested, i developed a simple bash script that allows a complete remotization of the unoconv converter (https://gitlab.di.unito.it/rabellino/unoconv_wrapper) that do not need the complex requirements on the moodle's side (only bash and ssh).
I don't like (and the new GDPR regulamentations too, i believe) that bigG can scan and do machine learning on all the student's assignments.