Why i need to create DbRefResolver while creating MappingMongoConverter if my schema does not contains any DbRefs?

So im trying to learn spring mongo data in-deep, and i have a question.
Why MappingMongoConverter requires a DbRefResolver in constructor?
And do i get it correctly that purpose of DbRefResolver is to resolve DbRefs annotation in some way?
My schema consists of 1 simple dao WITHOUT any db refs, does that means that created DbRefResolver is not used at all?

Code example

    @Override
    public MappingMongoConverter mappingMongoConverter(MongoDatabaseFactory databaseFactory,
                                                       MongoCustomConversions customConversions,
                                                       MongoMappingContext mappingContext) {
        DbRefResolver dbRefResolver = new DefaultDbRefResolver(databaseFactory);
        MappingMongoConverter converter = new MappingMongoConverter(dbRefResolver, new MongoMappingContext());
        // Don't save _class information in the mongo document
        converter.setTypeMapper(new DefaultMongoTypeMapper(null));
        return converter;
    }