Well, that's Jinja. And arguably not a bad tool, but not the best for the use-case of config-management.

Yeah, I just have this sentiment wishing that Ansible's author used own-crafted format. HashiCorp used their own and suddenly in this case no one says "yaml should be everywhere because it's everywhere already".

In a similar mood, I wished Kubernetes was staying every from yaml. Even mentioned HCL would be better (although it's not perfect)

Yes but the task names and parameters try to mimic natural language, like assert: that:, so you're supposed to read it as a whole, and it quickly turns into an abomination, with one syntax (yaml) for the structure and another (jinja) for values and conditions