In order to reduce the number of artifacts we are currently building when releasing a new version of https://github.com/ome/omero-insight, we are considering dropping the creation of OMERO.importer artifacts in the next release unless there are strong objections to it.
OMERO.importer was previously a separate application. For numerous releases, OMERO.importer and OMERO.insight have shared the same code base. OMERO.importer is a subset of OMERO.insight.
The size of the artifacts is the same.