I don't like it. I think.
That being said, my son does it. He has done it since the first time we went bowling together. He did it so easily, and learned to be accurate so quickly, that I had to figure it WAS natural for him to do it that way, and I always tell people not to fight what comes natural but learn to use it. As bad as it felt, I encouraged him to develop the style that felt natural to him, and never discouraged him from using it. He is only a recreational bowler, but can shoot over 200 with regularity. For him, it is as easy, and as natural, as breathing.
If someone were to tell him he couldn't do it that way, it would probably make me pretty irritated at them.
My experience with my son taught me that, while I disagree with that style, it IS a viable alternative to the traditional single handed technique, and it is a very natural style for some, that should be allowed even if some of us don't like it.
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Good transactions list in my profile