The recent discovery of rapid and high-quality synthesis of Gr at liquid Cu catalysts was an important finding towards large-scale commercialization. At present though, there is little mechanistic understanding of what precisely leads to the improved Gr quality as compared to the more traditional synthesis on solid Cu catalysts, which typically employs highly comparable growth conditions just at ~100 K lower temperature. The absence of extended defects, generally higher mobility of atoms, clusters, and flakes, or an increased carbon dissolution at the liquid Cu surface are but a few possible aspects that immediately come to mind. Therefore, detailed atomic-scale investigations are highly desired to further our understanding, carve out the governing factors, and then employ this for a rational improvement of the growth processa strategy that has long been successfully exercised for solid catalysts.