>"DB will do similar things" Not really as the storage data layout and application data layout are different. If I were to use database only relying on it's ca

>"DB will do similar things" Not really as the storage data layout and application data layout are different. If I were to use database only relying on it's caching abilities it would lead to complex queries that are definitely way less performant than getting data from in memory structures optimized for this particular application / usage patterns. On top of that some requests require some relatively complex calculations that again are executed against optimized in memory layout and would suffer greatly if done against the database. I did some experiments and the difference was very significant.