Binary mergers involving a binary neutron stars system can result in 3 kind of astrophysical source: a gravitational wave signal (GW), a gamma-ray burst (GRB), and a kilonova. The first and only (to date) optical counterpart of a gravitational wave source AT2017gfo is the first kilonova (KN) that could be extensively monitored in time both photometrically and spectroscopically. In contrast, approximately 10 KN have been identified in association to short GRBs, although none spectroscopically and with various degree of evidence. Here I present the current status of our understanding of the kilonovae associated to short GRBs, the current and future improvements in the field to best separate GRB and kilonova, also in light recent peculiar recent events. Moreover, I discuss the advantages of a dedicated GRB mission for the study of KN events.