IMO using different fonts for headers is not very applicable for scripts other than Latin/Cyrillic/Greek. For example on Arabic, we don't have two different ready to use font on every PC on web browsers. "sans-serif" and "serif" is not very applicable for Arabic/Persian and we have another typographical groups actually. For a web pages, almost Persian web sites are using same font for headers and text body. We may use another approach for printed documents (that are not "sans-serif" and "serif" actually) that can not be find on every machine but some also prefer to use the exactly same fonts (with modified weight and size) for distinguishing header from texts on printed documents.