queues

Utilization-based scaling is the wrong sensor when work arrives as backlog. The design questions are threshold math against drain rate, reaction-time bounds from polling, and why lag-driven fleets oscillate without generous targets and idempotent consumers.

It converts a synchronous failure into a delay. That is the whole benefit and the whole cost, because the caller now gets an answer before the work has happened and somebody has to tell them when it did.