It's not that easy a style to use and the practitioner has to have certain abilities to make it work. Quickness and speed are mandatory. The style is also too squared up which, while it makes combinations faster it provides a bigger target (Patterson was the most knocked down heavyweight champ ever, and mostly abandoned the style when he left D'Amato). Balance and back and forth movement are sacrificed somewhat, one writer (Liebling I think) compared it to a guy with a stack of plates trying to rush forward so they wouldn't fall. Beyond D'Amato and his disciples it never caught on with anyone else. I think it's really uncomfortable to hold the hands that high too, protects the chin but makes it harder to throw punches. The guys who could make it work were phenomenally fast (Tyson, Patterson and to an extent Jose Torres). Like anything else, it's not for everyone.