Of course, there are limitations. Firstly, there is no reason to expect good results if a sufficient active space is not chosen for all geometries. In the best case, one will reproduce HF-PBE, which may or may not be adequate. In the worst case, describing only some multiconfigurational states with good active spaces may result in an imbalanced treatment and actively worse predictions. How can one be sure that this is not the case? The APC (12,12) active spaces chosen in this work seem to have been sufficient for this application, but further development will be needed for application to larger organic complexes and transition metal systems. Ultimately, different approaches need to be tested on a wide variety of systems and investigated on a case-by-case basis to be trusted.