When you write a complex config with a lot of nested objects, you still need to use a lot of {} in MAML; (with YAML: https://github.com/Lavshyak/MaterialClassification/blob/master/MaterialClassification.MainWebApi/appsettings.yaml, much more compact and readable).
When you write a simple config, YAML is about the same.
In my opinion, the machine parses JSON faster than MAML (when data exchange between services for example).
So I don't understand why MAML is needed when YAML and JSON exist.