It feels more like a lowest common denominator to me, which is frequently (in presence of anything non-trivial) the opposite of idiomatic.

For example, JSON does not have monetary/decimal type, best option available is a string. It would be very opposite of idiomatic to have a C# or Python code use a string in the record/dataclass, instead of a decimal, if the actual JSON document field has the "monetary value" semantic.

And TypeSchema seem to ignore aspects like nullability and presence requirements, making assumptions that everything can be null (which can be wrong and even harmful, as if Java haven't taught us anything).

Maybe I'm thinking wrong about it and the idea is to have separate wire and public API formats, though, where the wire format is minimal JSON (TypeSchema can work, I guess, although I still have concerns about nulls - and distinguishing between nulls and absence of the field) and then that intermediate almost-over-the-wire-but-deserialized-from-JSON-blob object representation is adapted into a language-specific idiomatic structure. I always felt that such approach is way too verbose and adds a lot of boilerplate without a good reason, but I could be wrong about it.