So... When do you reach the point Where it's better to just use a hashtable in ram? Super high speed "in memory" databases are still beat by manipulating the da

So... When do you reach the point Where it's better to just use a hashtable in ram? Super high speed "in memory" databases are still beat by manipulating the data structures yourself. I feel like there's very limited applications where all out speed is important and it's better to use a database than just do the operation yourself in ram and save the network overhead. You can insert billions of items per second into a hashtable, and when you're working in your own app memory transactions aren't needed.