Better concurrency (10k vs ~200 max connections compared to postgres). ~20x faster than Postgres at Key-value read/write operations. (mostly) single threaded, so atomicity is achieved without the synchronicity overhead found in RDBMS.

Thus, it's much cheaper to run at massive scale like OpenAI's for certain workloads, including KV caching

also:

- robust, flexible data structures and atomic APIs to manipulate them are available out-of-the box

- large and supportive community + tooling