Roy,

With all due respect, this is the pattern sub-forum and there was a specific question about when and why one might want to use a 3-bladed prop. The original poster presumably asked it in the pattern (and not sport flying) sub-forum because he wanted to know the finer points of the topic.

The original poster has gotten advice and succinct explanations from some of the most knowledgeable people in the hobby concerning his question.

Why are you so concerned that somebody wants to learn something new? Why do you presume that the original poster is a noob sport flier and not a progressing competitive flier?