There are two answers to your first question.

1. Dynomite pairs well with Cassandra. At scale, Cassandra is not a speed deamon when it comes to reads. Dynomite helps to improve Cassandra's read performance.

2. The use case for Dynomite as the primary database is for workloads that require high throughput and low latency. In other words, Dynomite delivers consistently lower latency at any scale.