DDB has two use cases:

1. You need an "infinitely scalable" key/value store and have deep pockets[0]

2. you work at AWS and your deployment pipeline has so many stages and regions and fabrics that you can no longer even conceptualize what it means for there to be a "current version" of your software (the hell in which I live).

But for some awful reason it's sold as a general purpose "NoSQL Database." Pair that with the Pavlovian response developers have to the word "scale" and you've got an army of people using the worst possible tech for their usecase. Everyone eventually pairs DDB with Elastic whenever "Oh, wait, so we need to be able to query our data?" hits.

[0] And you ONLY need PK reads. Querying turns "infinite scale" into "infinite throttles."