Document based databases have a big advantage over relational databases as they do not require defining a schema upfront- before being able to enter any data.
Also, you should use a document database if you data is not relational and cannot be stored in a table but rather is a set of images, or for example newspaper articles.
Another advantage is the easiness to use document based databases in web development.For more in-depth NoSQL database models comarison check this source: https://arxiv.org/ftp/arxiv/papers/1509/1509.08035.pdf