We tend not to use things that are not "ready at hand."

RDF datastores are noSQL also :-)

I always keep Sesame running as a service just as I run PostgreSQL and MySQL services.

Some things are better stored, queried, and maintained in a graph database.

If you always have something like Sesame (or the free edition of AllegroGraph) running as a service, and if you have client libraries installed for your favorite programming languages then it is easier to quickly choose the best data store for any given task.

BTW, I also always keep a CouchDB service running.