Comment on "Nontrivial Quantum Geometry and the Strength of Electron-Phonon Coupling", arXiv:2305.02340, J. Yu, C. J. Ciccarino, R. Bianco, I. Errea, P. Narang, B. A. Bernevig

The titular manuscript invites a description of the background of research on MgB${}_2$,whose unique electron-phonon coupling strength and record superconducting T${}_c$ for such a material at ambient pressure was demonstrated by the combined efforts of several groups two decades ago in terms of conventional but highly developed Migdal-Eliashberg theory. This Comment provides some of the basic features of the theoretical understanding of MgB${}_2$ and draws contrasts with the model of Yu {\it et al.}