Establishing the veracity of the benchmarks is vitally important for the development of low-cost methods including density functional theory (DFT). Notably, various dispersion-inclusive exchange-correlation functionals and dispersion-corrected DFT approaches afford results of wildly varying quality for supramolecular complexes with 100 atoms, despite the fact that the same methods provide rather accurate interaction energies for small van der Waals dimers. First-principles dispersion models also need to be tested against highquality ab initio data in large systems.