If you're doing a "tracer bullet"-style method of development where the requirements aren't quite set in stone, MongoDB and other schemaless databases can reall

If you're doing a "tracer bullet"-style method of development where the requirements aren't quite set in stone, MongoDB and other schemaless databases can really save time when it comes to adding basic functionality quickly. Another use case: if you have an ad-hoc group of developers working on a project in a decentralized fashion, they can each work on local codebases of the project without needing an up-to-date setup script or migration scripts. I'd maybe even argue that a lot of these "goodbye MongoDB" developer blog posts are sort of unnecessary. MongoDB allows for fast deployment and the convenience of a flexible database at the cost of speed, so eventual migration to a more solid relational database could/should be part of a long-term plan when devs choose to use MongoDB. It's all about using the right tool for the job.