Do you know why the English Wikipedia doesn't use it? It is simply because the English Wikipedia information is generally better than the corresponding Wikidata information?
I believe it's simply because no one has yet put in the effort necessary to start using it. It might be a conscious decision, but if it was discussed anywhere, I completely missed that.
(English Wikipedians in general are very "territorial" in my experience, so to speak, and rarely appreciate efforts that put some piece of "their" articles beyond their "jurisdiction", like Wikidata does. Editors from other language versions are a lot more welcoming.)
