As your latency requirements go down, feasible storage sizes also go down. In this case the latency requirement is quite low: any time delay on lookup is direct

As your latency requirements go down, feasible storage sizes also go down. In this case the latency requirement is quite low: any time delay on lookup is directly added to packet latency. So the better comparison would be L1 or L2 cache, rather than on-disk storage for a database.