What is the new airflow_settings.yaml file for?

Can i do this to make a gcp connection?

airflow:
  connections:
    - conn_id: 'google_cloud_default'
      conn_description: 'google_cloud_default'
      conn_type: 'google_cloud_platform'
      conn_keyfile_json: '{"type": "service_account","project_id": ....}'

Im trying the above and its making the connection but not looking like the keyfile json is getting thorough

Is this functionality still supported? And is it recommended over using a secrets backend?