Requirement:

A developer should be able to set controller_host : {{ awx_controller_node }} and not bother unless the said transaction is on another co-hosted platform.

Your document says –
automation controller automatically adds the following variables to the job environment. Also note, awx_``* variables are defined by the system and cannot be overridden. Variables about the job context, like ``awx_job_template_name are not affected if they are set in extra_vars.

But for the moment it only defines and sets awx_execution_node

Why should one need to pass static value for controller url in each environment when the same can be easily auto discovered and made available by the platform.

Use case –

We are trying to build modular plays that can be exposed as Job Templates. The recommendation provided by RedHat was to use ansible.controller.job_launch collection instead of using URI module.

However, the same also requires passing URI, Username and Password or Token with an excuse that the module ultimately make api calls in the background and we want to see if the value can be made available as a default environment variable.