When North Beggar Hung 7 Gung named Wong Yung as his successor as Chief of the Beggar's Union, he picked her because he felt she was capable of leading the Union, but also because she was the only person around. At the time, Hung 7 Gung thought that Gwok Jing was dead.
As it turned out, Wong Yung was a very good Chief for the Beggar's Union. It wasn't always smooth, however, especially at first: many of the senior beggars were not content to follow the orders of a teenaged girl (especially the daughter of the infamous East Heretic Wong Yerk See), at least until she proved herself.
What if Hung 7 Gung had named Gwok Jing as the next Beggar's Union Chief, however? Would it have worked out better? Granted, Gwok Jing would still be relying on Wong Yung's brains to plan things out, but would having him as the "face" of the Union have gone over better with the rank and file beggars?