This pattern keeps repeating because the creators of an app think they need a configuration language (which some users do) and then when eventually other users end up needing an API or some feature the config language doesnt have. They both dont exist so they hack it with templating.

It's often quite hard to know what kind of problems need an API and what kind of problems need configuration. It's sometimes only obvious in retrospect - the same point when you also get held back from changing things by backwards compatibility and culture.

The reverse problem (no configuration, only turing complete code) carries its own set of problems and can be just as infuriating. Getting the balance just right is hard and often only clear in retrospect.

Kubernetes really should have done something about the templating horrors by now though.