Does JSDoc even have a type checking system? The point of TS is that is actually does something with your declared types. JSDoc is nice... for docs being interpreted by a human. But unless those are used to create red squigglies then it's kind of arbitrary.

I've used JSDoc with TS's type syntax and typechecker in JS files. Which is fine - I find it subjectively uglier but I know some prefer it. But it's still TS that's doing the actual work of determining if all my annotations are compatible when the rubber hits the road.