Man I love graph abstractions and database, but the inevitable questions comes - why HBase? Why not use a database that isn't nearly impossible to set up?
The primary motive for writing this was the fact that Hbase gives a fairly cheap(hdfs) backend storage and near linear scalability. Also most of the schema is encoded in row keys in such a way that hbase prefix scans can be leveraged to serve traversals across billions of nodes/edges.
Maybe you are correct, Hbase is not easy to configure for sure but in terms of scalability (sheer number of row keys you can dump) there are not a lot of other components which can compete.
Although theoretically this abstraction can live on top of any backend which has facilities for fast prefix scans.