If orbitals that are delocalised over the entire compound system are utilized as one-electron basis, a simple ππ * excitation on one fragment can only be represented by a large linear combination of excitations across most (if not all) delocalized MOs, artificially coupling them to each other and, thus, producing unnecessarily complicated CI expansions, featuring long-range entanglements. On the contrary, fragment-localized orbitals keep the leading forms of electron correlation confined within each fragment, increasing the sparsity of the wave function. We also note that for systems made of weakly interacting fragments, such as the benzene stack, and using a GAS strategy that reflects the fragment nature of the compound, the Stochastic-GAS calculations are practically size-extensive if localised orbitals are used, because we can safely assume that only inter-space excitations into the same stack are relevant.