Hot take: YAML isn't a configuration language or a configuration language format, it's a serialization format. Is de-serializing some data structures the best way to configure a program? Maybe not. (Probably not. Mostly not.)

Like programming languages, all configuration systems communicate with both the computer and other people. But most are designed only for the computer to consume, not to be clear when people read it. De-serializing your live data structures is an extreme example of this.