When you are creating MVPs time matters the most. You are anyway going to throw it away and build something better.

I was using Mongo and NodeJS a lot but then switched to Python. Now I find the world of ORMs to be onerous. I just want to define tables in MySQL and just run raw SQLs. The best compromise I have found so far. I mean it does involve boiler plate code but ultimately it's an MVP.

And you are right, most of MongoDBs uptick was because of the reasons you state. E2E Javascript and in addition the ability to query nested JSON natively.