> If the request is Important, you certainly don't want to trust it to a message queue, a device not really designed for the storage of messages.

That's false. Virtually all MQ systems are designed to persist (often with replication/redundancy) and store data. Most MQs also support non-persistent delivery, with the cost/benefit (ephemerality/performance) that entails, but that doesn't mean that durable storage is any less well-supported.

Sure, folks have plenty of operational war stories regarding failures of persistence in their MQ broker/cluster/whatnot. Same as the DBAs who manage relational databases.