Ask HN: Why are you using MongoDB?

After postgres has implemented JSON/JSONB support, I feel like there is no need to use mongodb and the likes. Given all other benefits of postgres (acid, tooling etc) it feels overall it's better suited for cases where you'd use mongo for.

I heard stories where people would just start with mongo and eventually migrate to more mature tech as they go, but that need seem to have evaporated.

Thoughts?