DB isn't needed. Our microservices pipeline either uses MQ, EFS or S3 for the destination for another pipeline to pick up. Unless you count those 3 as DBs ;)

Yeah I would say those are key value document based DB. Just silicon valley hipster coming up with cool names to call something different so it is a bit easier for developer to use. Anything does permeant storage are DB.

You could argue S3 is a key-value store, however ActiveMQ is a message queue, and EFS is essentially NFS.

I certainly don't agree that 'anything that does permanent storage is a DB'. Not many people would call their hard drive a 'database'

I personally think that they all have a place and are very useful tools for certain situations, depending on the problem.