If the question is about whether JSDoc is TypeScript, and you want to turn it into a different question, maybe your question belongs in a different thread.
JDoc, the spec and docs-in-practice, is not TypeScript, the language and tooling ecosystem in practice, and does not have type annotation parity with TypeScript (so it's not even "the choice is arbitrary in practice because they do the same thing").
JSDoc is simply a supported spec by the TypeScript tooling. Saying "JSDoc is TypeScript" when you're a programmer, especially one that uses one or the other, is idiotic: your job relies on precision in both code and terminology.
JDoc, the spec and docs-in-practice, is not TypeScript, the language and tooling ecosystem in practice, and does not have type annotation parity with TypeScript (so it's not even "the choice is arbitrary in practice because they do the same thing").
JSDoc is simply a supported spec by the TypeScript tooling. Saying "JSDoc is TypeScript" when you're a programmer, especially one that uses one or the other, is idiotic: your job relies on precision in both code and terminology.