It sounds like the author didn't have experience with larger systems In actual _large_ systems like Facebook or Google you explicitly keep runtime applicaiton

It sounds like the author didn't have experience with larger systems In actual _large_ systems like Facebook or Google you explicitly keep runtime applicaiton configuration info out of the config management system and use another system entirely to manage that. This lets you easily manage test/deploy, shard services easily, and do rolling deployments with config info updated instantly across the fleet if necessary.