Dynamodb is very scalable and effective at keeping operational cost down. It succeeds at it's goals by trading off on lots of things though. As a developer it can feel almost hostile. Adhoc queries are limited almost forcing you to have a complete second copy of the data. Access patterns must be designed up front and hope you don't need to change much when you hit scale. The tooling is meh. It's easier to make a scalable database when you push all those problems on your devs. Constraints are tricky. Transactions must be carefully designed. It's nice to know that almost definitely read and write throughput will scale and you can reduce the DBA/DevOps staff because AWS handles it.