We would rather like to support linking and data integration with external data bases than suggest *every* fact of the world to be copied to Wikidata.
An interesting example is the IUCN redlist of threatened species: http://www.iucnredlist.org/ Data are modified by IUCN from time to time, so copying would be a rather temporary solution, while the redlist status is important in infoboxes of animals and plants.