The major problem with dead letter queues is that people naturally end up mixing recoverable and non-recoverable errors together, which results in all errors be

The major problem with dead letter queues is that people naturally end up mixing recoverable and non-recoverable errors together, which results in all errors being ignored. Proper monitoring typically requires application specific details and logic, which queues, being a dumb bus, typically don't have. E.g. your client has a scheduled downtime every midnight, so you want your monitoring to not alert on messages produced by account X between 00:00 and 02:00. Oh, and ideally these exclusion rules are set up by non-technical folks (maybe even by customer himself).