In a recent paper [Physical Review B 100, 165105 (2019)], Yuriko Baba et al. investigate the consequences of applying electric fields perpendicularly to thin films of topological semimetals. In particular, they consider Weyl and Dirac semimetals in a configuration such that their surface Fermi arcs lie on opposite edges of the films. They develop an analytical approach based on perturbation theory and a single-surface approximation and compare their analytical results with numerical calculations. The effect of the electric field on the dispersion is twofold: It shifts the dispersion relation and renormalizes the Fermi velocity, which would, in turn, have direct effects on quantum transport measurements. Additionally, it modifies the spatial decay properties of surface states which will impact the connection of the Fermi arcs in opposite sides of a narrow thin film.