Keiran, thanks for your comments! As you pointed out, relational databases are great for analytics / financial stuff. It allows transactional correctness as you suggest, and it also has the benefit of providing the programmer with a rich, expressive query layer which allows you to put forth complex ideas as small declarative queries. From a startup’s perspective, this expressiveness saves a LOT of development time, assuming the developer knows how to use it. Sadly, people still use MySQL / Postgres as a primitive object store.