XML aims to be both human-readable and machine-readable, but manages neither. It’s only really worth it if you actually need the complexity or extensibility, otherwise it’s just a major pain to map XML structures to any sensible type representation. I’ve been forced to work with some of the protocols that people like to present as examples of good XML usage and I hate every single one of them.
Fuck YAML though. That spec is longer and more complex than any other markup language I know of and it doesn’t have a single fully compliant implementation.
I wouldn’t recommend Docker for a production environment either, but there are plenty of container-based solutions that use OCI compatible images just fine and they are very widely used in production. Having said that, plenty of people run docker images in a homelab setting and they work fine. I don’t like running rootful containers under a system daemon, but calling it a giant mess doesn’t seem fair in my experience.