Hoi,
While Wikipedia is not a primary source, many of the assertions in Wikipedia have sources. When sources in Wikipedia (either directly or through DBpedia) are added to Wikidata, the assertions will be a great start for curating these facts. In my opinion there is nothing wrong with starting with the assertions in Wikipedia (are all Wikipedias equal ??).
Relevant is that we need labels in Wikipedia in any and all languages. This means that we seriously need a multi lingual community... we seriously need a community and we may get such a community when we make sure that Wikidata is a project in its own right.
Again, adding sources to assertions is important but we are starting with unsourced assertions and growing a community that has an interest in Wikidata for its own sake as well as for the application of assertions elsewhere (not only in wikipedias).
Thanks,
GerardM