1. I want to deploy to a testing environment where I may want to use different users, different sized services, or even mock services so I don't have to pay for them? 2. I want to develop in an isolated environment (maybe without internet or simply I'm trying to develop a narrow feature that doesn't require the rest of the infrastructure)? 3. How does it handle security elements like VPCs, IAM roles, all these things that are the context my application runs in that I don't necessarily want to couple to my application code?