For fault-tolerance in case the box is unresponsive for whatever reason, I think you would have to have a network behind a load balancer. So the issue of network latency still exists, but probably to a lesser extent?
Yes, obviously some things will need to be persisted, and some of those things might be some of your queue entries -- so a persisted network queue (and network things to dequeue from it) can definitely be a necessity for that reason as well.
