Why build The Cheater of Mystra?

The Cheater of Mystra is a very well-known 3.5e CharOp build. To my knowledge, it dates back to this post from 2004 and almost every description of the build that can be found online is a copy and paste of this post. However, the benefits of having this build do not seem to be described in much of the literature on the subject. It appears to be something to the effect of being heavily buffed at all times and being able to ignore your own AMF. But, for fear that the rabbit hole goes deeper than I suspect, I am asking here. What features of this build make it significant among optimised Cleric builds? In other words, why build The Cheater of Mystra?