[parliament32]

Mongo is the wrong choice for a solid 75% of the places it's used. In the vast majority of cases, it was brought in to replace a relational db because developers though it would be faster to not have a schema / constraints / relationships, etc. It usually lets you develop faster, at the cost of blowing up in your face a few months/years down the line, when you have to rebuild your app to use a real database because your devs remembered why relational dbs are useful in the first place.

Mongo is a document store, not a relational db. Mongo is a good choice if you're looking to replace ElasticSearch, not if you're looking to replace MySQL.