I was of the roughly same opinion, especially after getting familiar with relational theory. Despite all the horrors of SQL-the-language, the backing model is c

I was of the roughly same opinion, especially after getting familiar with relational theory. Despite all the horrors of SQL-the-language, the backing model is close to being universal for data storage and manipulation. Having said that, we did encounter one good use case recently: storing tree-like documents complete with history changes. Mongo-like DBs are really good for this. While possible in relational DBs, this is superinconvenient. Notably, this has nothing to do with performance.