Most people only have so much “working memory”, and thus can only hold so much information actively at once before things start “falling off the table”. By using an external aid like “crazy wall”, chalkboard, or even a simple doodle on a napkin, one can visualize more information at once. If it seems chaotic, well, it kind of is; just as each brain is unique, each “crazy wall” only makes sense to the person who made it.

Those of a particular type of intellect have no need for such things; they serve merely as eye candy for the TV camera. That is why the BBC series Sherlock uses the “Mind Palace” instead, as does Dr. Hannibal Lector, and most non-fictional super-memorizers. But for those whose intellect falls short of the top 0.01% of humanity, it’s a useful tool to aid deduction by presenting more facts simultaneously.