A major use case for LocalStack is CI/CD.

When you're running hundreds of integration test suites per day in CI pipelines, the free tier is irrelevant. You need fast, deterministic, isolated environments that spin up and tear down in seconds, not real AWS calls that introduce network latency, eventual consistency flakiness, rate limits, and costs that compound with every merge request.

It'd be great to just use AWS but in practice it doesn't happen. Even if billing doesn't, limits + no notion of namespacing will hit you very quickly in CI. It's also not practical to give every dev AWS account, I did it with 200 people it was OK but always caused management pain. Free tier also don't cover organizations.

> they MUST learn that there are no hard spend limits, and the only way to actually learn it, is to be bitten by it as early as possible

This is a bizarre take. "The best way to learn fire safety is to get burned." You can understand AWS billing without treating surprise charges as a rite of passage.