• repeatability (subtly different from reusabilty)
In my experience configuration drift is often not fully eliminated automatically*, but IaC definitely helps. Same for budget-friendly: it's not a silver bullet.
* Running unattended scheduled pipelines to "fix" things can be risky as Terraform isn't always aware of "content state" when it has to recreate resources. Also, I've recently had Terraform creating resources and then running into an error before writing to the state file what it had already created successfully. Result: orphaned resources (Terraform actually caused the config drift). Note that these are exceptional cases, most often it works fine.