Why doesn SMW use SPARQL as its query language?
SPARQL is the main query language of the semantic web, and it’s more flexible overall than SMW’s native query language; using SPARQL would also prevent users from having to learn yet another query language. However, using SPARQL would allow for complex queries that are currently not allowed in SMW, due to their impact on performance. SPARQL already can be used on SMW data, though, via the RDF export, or the RDF data store. SPARQL queries can even be run directly on wiki pages, via the SMW+ Triple Store Connector.