GP seems to be implying hot swapping, not Erlang, is unreliable. To which, from my experience using it in Erlang, I heartily agree is fraught. Inconsistent state across nodes is much harder to reason about. When you _must_ ensure consistency, hot swapping is reckless, especially as org size and product complexity increases.

Leave hot loading to local/development environments, not production deploys.

Loading configs on the fly can also have some of this risk, but it is much easier to reason about typically.