> a minimum of effort

That is not a combination of words that should be mentioned in the same sentence as the word XML or, even worse, XSLT.

XML has its value in enterprise and reliable application development because the tooling is very old, very mature and very reliable. But it's not something taught in university any more, it's certainly not taught in "coding bootcamps", simply because it's orders of magnitude more complex than JSON to wrap your head around.

Of course, JSON has jsonschema, but in practice most real-world usages of JSON just don't give a flying fuck.