Our cynical view, honed from experience, is that any quantum chemistry method that require physicsbased decisions is too sophisticated for the average user. Too often, however, we feel that DFT calculations are used to reverse-engineer "explanations" that confirm preconceived expectations, sometimes shopping around for an XC functional to achieve that result. This is a lousy approach in any case but it is supremely dangerous in the context of EDAs, whose energy components do not correspond to observables and thus cannot be interrogated directly against experiment. Nevertheless, the well-defined nature of the XSAPT energy components facilitates comparison with SAPT2+(3) calculations, whose energy components may not be directly verifiable but whose total interaction energies are in good agreement with CCSD(T) results, for reasons that are grounded in many-body theory. Such comparisons are discussed in Section 3.2.