In principle, whether obtained with GTOs or PWs, CBSconverged energies must be identical. However, fundamental differences exist between those two types of basis functions and have never been thoroughly compared. We hence attempt to fill this gap with the present work. More specifically, due to the CP correction and extrapolation schemes required for GTOs or due to some peculiarities of PWs in the treatment of isolated systems (where the interaction between periodic replica intrinsic to plane waves have to be explicitly removed), it is fundamental to clarify how the results obtained with these two different approaches may differ in practice. To answer this question, non-covalent interaction energies of dimer systems provide a sensitive test case, because the description of weak dispersion interactions often requires an accuracy of the order of 0.05-0.5 kcal/mol . Such systems thus challenge the ability of a basis set to best capture the short-range components of the correlation energy around the Coulomb cusp while at the same time incorporate the long-range features of the intermolecular interactions. A priori, the delocalized and balanced nature of PWs seems more appropriate for such a treatment of e.g. hydrogen-bonded and van der Waals complexes, but at the cost of a much larger number of basis functions. On the other hand, polarization and delocalization of the electronic wave function necessitate larger and/or augmented GTO bases for a better coverage of real space . If these effects are accounted for, the presence of diffuse functions causes the basis set to be more prone to the BSSE, which also makes non-covalent interactions a problem of choice for examining the effect of the CP correction.