It’s not flow control so much as sane, expression-based generation of resources.Terraform has been evolving toward the dynamic with features like for_each, but these features have awful ergonomics compared to something like list comprehensions. Similarly, sometimes you want to reuse some pattern, but the unit for reuse in terraform is the modules which involves a lot of ceremony, so you don’t reach for it as often as you might if the unit of reuse was a simple function definition.

I don’t especially care if Terraform is a simple static language for generating resources and the DRY-ness comes from an exterior Python/etc script that generates the Terraform files or whether the requisite dynamism is built into the terraform language itself, but make no mistake, the dynamism is absolutely essential for maintainable terraform.