http://traducciones.inglesk.com/2015/05/learn-kanji-hanzi.html?m=1
Heisig’s method focuses only on you learning the writing and rough meaning of each character. While it may seem that not working on the Japanese/Chinese readings renders Heisig’s method incomplete or even useless to some people, the method focuses exclusively on the recognition and writing of the kanji/hanzi for a very specific and important reason.
In a nutshell, through Heisig’s method you gain the same advantage that a Chinese person would have for learning Japanese from scratch, or viceversa:
People from China/Japan are already familiar with most kanji/hanzi characters, and relate each one of them to a certain concept in their own language.
Thus, already knowing how each kanji/hanzi looks like, and what they mean, they only need to learn how to read them in the other language they want to learn.