Quantum dancing monkeys? Valence bond theory of benzene

Hopefully this will be the first of several posts related to valence bond theory. I attach a nice treatment of a simple Heisenberg model for benzene, copied from a book, Electronic Properites of Conjugated Polymers by William Barford. The book also shows how strong electronic correlations lead to a significant different ordering of excited electronic states than predicted by molecular orbital theory and density functional theory based approximations. So what does this have to do with dancing monkeys and quantum entanglement?