The main advantages of XML (or any standard) is adoption and a wide ecosystem. Unfortunately that beats any "better" standards by a wide margin. One thing that

The main advantages of XML (or any standard) is adoption and a wide ecosystem. Unfortunately that beats any "better" standards by a wide margin. One thing that is also really important is the ability to define a schema and be able to validate. See XML Schema, JSON Schema. This is a really tricky problem to get right. Especially if you try to do both with the same model (describing your data model and describing how its validated) at the same time. Once you have the schema, IDEs like VSCode offer code-intelligence and real-time validation, which is very nice.