It may be true to an extent, but the purpose of the inquiry would be the value gained if one could both IDENTIFY one's own core beliefs and purposefully/willfully change them. Without being able to identify them, I think it might not be as powerful, and might also prove quite difficult at least from the "useful" sense. By useful I am sort of suggesting we would favor PREDICTABLE change. And to predict the change, we might likely need to know what we are changing.