Per conversation with @jaymode, the cat API is intended for consumption via Console and the command line. It's not intended for consumers who are writing application code.

Kibana consumes the cat API at numerous points (example: elastic/kibana#56532). To help Kibana engineers (and other application developers) migrate away from cat and avoid consuming it in the future, I think we should update the docs with a clear explanation of the purpose behind the cat API, including details on why it's problematic to consume it in application code, and advise application developers to use the other APIs.