Currently Wikidata is only set up to directly serve data to Wikimedia projects.
The goal of this project is to also allow 3rd party clients to consume Wikidata data in the same way.
Possibly this could work similar to InstantCommons (https://www.mediawiki.org/wiki/InstantCommons), which is a way to use Wikimedia Commons content on third-party wikis.
We could have implementations of EntityLookup that access entities via the api and would work for this use case. Unless we have some cache invalidation mechanism, Wikidata content in third party wikis would only be updated when pages are purged or edited. (might be sufficient for initial implementation of 3rd party access)