I can't really follow those arguments either. For example the empty object example {}. Why is this bad? Types without properties are a real thing. Also an empty schema is a real thing.

The thought I do get: JSON Schema primarily describes one main document (object/thing). And additionally defines named types (#/definitions/Student). But it's totally fine to just use the definitions for code generation.

The reference semantics of JSON Schema is quite powerful, a little bit like XML with XSD and all the different imports and addons.