If you want to use that for unit testing, then I think it would be better to mock the calls to AWS services. That way you test only your implementation, in an environment you control.
If you want to use that for local development, then I think it would be better to provision a test environment (using Terraform or any other IaC tool). That way you don't run the risk of a bug slipping into prod because the emulator has a different behaviour than the real service.
If you want to use that for unit testing, then I think it would be better to mock the calls to AWS services. That way you test only your implementation, in an environment you control.
If you want to use that for local development, then I think it would be better to provision a test environment (using Terraform or any other IaC tool). That way you don't run the risk of a bug slipping into prod because the emulator has a different behaviour than the real service.