That's not to say that MongoDB isn't high performance, but its place probably isn't serving blogs.
NoSQL definitely has its uses. But it's definitely not the answer for everything.
The main advantage of NoSQL is the easily changeable data model.
If your DB is 3NF and you don’t do any joins
(you’re just selecting a bunch of tables and putting all the objects together,
AKA what most people do in a web app),
MongoDB would probably kick ass for you.
Links:
https://stackoverflow.com/a/4982487/935330
https://realpython.com/introduction-to-mongodb-and-python/