IMO it is more a response to Microsoft with its PowerBI + DataZen products.
The Google Data Studio is only for dashboards (i.e. static visualizations) these other tools offers standard BI operations like rollup, drillup, pivoting and etc.
I use both Metabase and Redash in the company that I work for.
Both are really great tools and can replace (at least in part) expensive BI tools.
I'm using both not because they are complementary, but at this moment they have a distinct feature set and no one has all the features that I want/need.
It is(was) a company and its main product was a SQL client with built-in visualizations and features to save queries (just the query not the RS) in their cloud and share these queries with others peers in your organization.
In my opinion it was a very good product... Sad that they didn't open sourced it. =/
http://redis.io/topics/persistence