There are two main reasons: 1. If you're dealing with JSON, a native JSON database provides a 100x better programming experience than a relational system. 2. S

There are two main reasons: 1. If you're dealing with JSON, a native JSON database provides a 100x better programming experience than a relational system. 2. Scalability out of the box. You can just add a node, reshard, and keeping going. It's much harder in relational systems. If you have lots of null columns, hierarchical relationships, or eventual need for scale out, give RethinkDB a try. If you have traditional rigid data or ACID requirements, stick with a relational DB. Hope this helps.