@drscriptt At one point we were told that it was theoretically possible to directly employ someone in a non-local jurisdiction but it would require the university's lawyers agreeing to sign off on it, which would require very senior leadership approval, which was effectively impossible. Having the person involved¹ form a single-person consulting firm and retaining/paying the firm was Much, Much Easier.
¹ They moved back home but we wanted to still tap their expertise for a while.