[kmac_]

JSON is great, but lacks one feature that XML and its ecosystem has - extensibility and deep standarisation. XSLT, XML Schema, XML signing and encryption, native support of ids and refs, etc. All that missing points are doable with JSON or were added quite late, but yeah, standarisation is important.

[pjerem]

JSON somehow have standardisation with OpenAPI.

But yeah, JSON is a pain. XML was pretty smart.