A Hong Kong Notary Public is a internationally recognised trusted authority. International and Trusted Character of a Notary Public Notaries are granted the capacity and power to act in international transactions, foreign or oversea instruments Their qualification is internationally recognised.
A notarial act has special evidential status and weight abroad. Notaries create records and preserve evidence of activities, agreements, transactions, and events. "... a Notary is an internationally recognised legal officer who can authenticate signatures documents and facts."
A China-Appointed Attesting Officer has a more limited scope of business. It only handle acts, matters and documents emenating from Hong Kong and for use in Maindland China. For "notarial" acts usually done by a notary public, you must find a China-Appointed Attesting Officer to deal with these if the acts, matters and documents are for use in Mainland China if the same are from Hong Kong.