The value is...
... in being able to easily save values/data to a DB without having to pre-define a schema and jump through all of those hoops. It's MUCH easier and faster to develop when you don't need to deal with that. The trade off is that your documentation becomes much more critical and it's harder to work with other apps using the same data as a result. I suggest that you take a deeper look into "NoSQL" databases, since there is a lot more to them than how you access them, you may well find value in them for your projects.
J.Ja