These aren't "big data" features but rather EDW/BI features.
If PostgreSQL can't trivially scale horizontally like Cassandra or Riak or integrate nicely with Spark/Hadoop like MongoDB then it isn't particularly useful in typical big data roles.
Well something not mentioned in this article is the that 9.5 should also introduce inheritance from/to Foreign Tables which is one step closer to nice and easy horizontal scaling.
Maybe thats not a No-SQL trendy way of doing things, but for I am more used to PostgreSQL this look pretty neat. I think as the old and reliable project it is it will come to BigData at its own pace and quietly... but its already moving toward this and FDW was the first step.
If PostgreSQL can't trivially scale horizontally like Cassandra or Riak or integrate nicely with Spark/Hadoop like MongoDB then it isn't particularly useful in typical big data roles.