One kinda-exception I'd like to raise: Cases where you'd like to use the regular proper programming language from the very beginning, but there are trust issues, and there's no good/reliable sandboxing option.

For example, B2B stuff where every customer has their own idiosyncratic sets of rules for if-this-then-that, which change at a different cadence than your releases.

In those cases, it's less that configuration slowly becomes too complex and evolves into code, and more that code is wanted from the get-go but configuration is the compromise.