You should at the very least be doing analytics queries on a replica, or you could be affecting the database performance (and the customer experience) in produc

You should at the very least be doing analytics queries on a replica, or you could be affecting the database performance (and the customer experience) in production. But even if you did that, you'll find that you'll need joins and aggregations that are painful to do in Mongo yet trivial to do in a system that is designed for them.