The first theoretical volcano plot in electrocatalysis was developed on the basis of computed thermochemical data by Nørskov and coworkers. Two decades after this seminal work, the underlying thermodynamic methodology is still widely viewed as the established go-to approach for predicting activity trends in heterogeneous electrocatalysis. The methodology owes its popularity to its elegant simplicity, requiring the calculation of only few formation energies for each of the surface-bound intermediates assumed along the reaction path. These intermediates are most often treated efficiently as charge-neutral within periodic density functional theory (DFT) while viewing the mechanism as a series of proton-coupled-electron transfer (PCET) steps, i.e. reaction steps involving the concerted transfer of a (H + + e -) pair. The effect of potential is then conveniently included at the level of thermodynamic reservoirs in a post-processing analysis via the well-known computational hydrogen electrode (CHE). The resulting potential-dependent energy path provides insight into which mechanistic step is the thermodynamic bottleneck of the overall reaction, i.e. the identity of the so-called potential-limiting step. This insight has proved immensely valuable in establishing reaction principles and trends, as well as rationalizing experiments and guiding catalyst design. Despite its countless success stories, however, the limiting potential analysis has been known to fail when it comes to more subtle aspects of the underlying mechanism, such as the product selectivity.