> It spins up containers that simulate your tech stack, but it won't be an exact replica of your production infrastructure. For example, if you use a managed postgres DB in AWS in your prod environment, in a Dockup environment, you would use a postgres Docker container that's started using the official postgres image.

I don't quite understand this. Why wouldn't I want to spin up another postgres DB in AWS for testing?

I think that's what I'm a bit stuck on. Being able to spin up a test environment on demand is cool. But if I'm going through the effort to do that, why not go through the effort to do the same for a production environment? Then I can use the exact production configuration to run my tests.