The term "wonging" has become synonymous with back counting, entering a game at an advantage and exiting when there is no longer an advantage. This means the player is always playing with an advantage and could flat bet and win. BUT it also quickly become pretty obvious, even with a team approach.
I could be wrong, but my interpretation of "wonging" is more of an umbrella thing. And one of the pieces under that umbrella that is much less talked about and implemented, but just as valuable is "wonging out". This would be exiting at some predetermined negative count to escape at least some (the worst) of the negative counts and situations.
The wong out approach, while not enabling the player to flat bet, because he is always at an advantage, reduces the negative rounds allowing for a smaller spread, which can dramatically increase longevity. It is also far less obvious than the pure wong in, which again, is about longevity. So in my mind, a wong out approach might just be one of the top tools for a card counter....certainly has been for this professional player.
And if you include the "wong out" under the umbrella of Wong approach, then there are many more of us players, especially professional or at the higher end that implement a Wong strategy.