It is, but the problem is whether you are talking about an individual language version of Wikipedia or the Wikipedia project as a whole. In the article they talk about the problem of maintaining Interwiki links on each individual language version, rather than centrally.
This is also just one aspect of Wikidata. The centrality of shared table content is important, too. Why have data in a specific language version Wikipedia and point to it from other versions when you can have a central repository that is pointed to using templates from each language version?
This is also just one aspect of Wikidata. The centrality of shared table content is important, too. Why have data in a specific language version Wikipedia and point to it from other versions when you can have a central repository that is pointed to using templates from each language version?