Maybe it’s because I’m not a top 1% intelligence that I don’t get this but under what circumstances would configurations become complex enough to where this becomes necessary?
But wait the product have multiple regions. For each region we will depend on regionalized database etc to improve reliability. We need to have some sort of "mixin" so that certain command line arguments can be consistently applied to all jobs in that region.
And then SWE want to rollout a new feature, as the first step they want to roll it out in one data center first then move to full prod later. Now you need to have a data center level overrides.
Can all of these be done in a generic programming language? Yes sure, but why not use a language that intentionally limit what you can do, is almost side effect free?