cocos2d-x2.1 About CCUserDefault?

in 2.04 use:
// create new xml file
bool CCUserDefault::createXMLFile()
{
bool bRet = false;
xmlDocPtr doc = NULL;

do
{
// new doc
doc = xmlNewDoc(BAD_CAST“1.0”);
if (doc NULL)
{
CCLOG(“can not create xml doc”);
break;
}

    // new root node
    xmlNodePtr rootNode = xmlNewNode(NULL, BAD\_CAST USERDEFAULT\_ROOT\_NAME);
    if (rootNode  NULL)

{
CCLOG (“can not create root node”);
break;
}

// set root node
xmlDocSetRootElement(doc, rootNode);

// save xml file
xmlSaveFile(m_sFilePath.c_str(), doc);

bRet = true;
} while (0);

// if doc is not null, free it
if (doc)
{
xmlFreeDoc(doc);
}

return bRet;
}
Why not use the 2.1 version of it in this way?