It allows you to get started amazingly fast and has great client support. You don't have to think much about the DB side of things - just throw data into it.

It allows you to get started amazingly fast and has great client support. You don't have to think much about the DB side of things - just throw data into it. It's also where people get into trouble. After they've done this and built their MVP they don't go back and rethink their data decisions. Then scale issues occur, among other things. But it's also very easy to change your schema while iterating to serve your use cases better. But it's up to the users to change things and to learn which types of patterns scale better and to actually learn how to use the database to their advantage after gaining some experience. Learning how to model documents effectively is rather important.