I think the notes lost some context there—what I called “rocket science” was actually hand-authoring type definitions (e.g. for DefinitelyTyped) that work for a package that ships CJS and ESM side-by-side, and my point was that being able to redirect type resolution (to a separate module definition for each module kind) via export maps is going to be a super nice feature for us, and for type definition authors.

(Also, rocket science was probably a bad analogy, since I assume that rocket science is meticulous, precise, and reliable 😬)