Likely a 12 factor legacy issue.

https://12factor.net/

This was really popular, and lots of people bought the factor III of only configuring via environment variables.

The whole point of it was: keep config simple. Env vars are austere and will keep you from complexity.

But people found a way to complicate them, so they could have both the 12 factor literal pass and the complexity they wanted.

That resulted in the mess we are today.