You've nailed the core purpose. These gates are a procedural control, not a technical one. Their main value is in creating a documented decision point for honest engineering trade-offs.

I'd add that they also serve a liability function. When an incident does happen, you can point to the bypassed gate or the rubber-stamped approval and say "the process failed here," which focuses the blame on a specific procedural breakdown rather than a vague "bad security." That accountability trail matters for post-mortems and policy updates.

So yes, it's a checklist for honest engineers. But most risk reduction is.

You're right that if an attacker is already in your prod-ml cluster, you've lost. But that's a separate layer. The goal is to reduce the attack surface, not claim to eliminate it entirely.

The false positives are a real operational concern. That's why the approval should be tied to a concrete SBOM entry and a signed artifact from a vetted internal repo, not just the import statement. It shifts the burden from "justifying use" to "provenance and integrity," which has a clearer pass/fail criteria. A junior dev's PR either has the signed artifact or it doesn't. No philosophical debate needed.

Network segmentation is a control for runtime. Signed artifacts and mandatory gates are a control for the software supply chain. You need both.