MoonBEAM is a SmallSat concept placed in cislunar orbit developed to study the progenitors and multimessenger/multiwavelength signals of transient relativistic jets and outflows and determine the conditions that lead to the launching of a transient relativistic jet. The advantage of MoonBEAM is the instantaneous all-sky coverage due to its orbit, which maximizes the gamma-ray transient observations and provides upperlimits for non-detections. Earth blockage and detector downtime from the high particle activity in the South Atlantic Anomaly region prevent gamma-ray observatories in low Earth orbit from surveying the entire sky at a given time. In addition, the long baseline provided from a cislunar orbit allows MoonBEAM to constrain the localization annulus when combined with a gamma-ray instrument in low Earth orbit utilizing the timing triangulation technique. We present the scientific performance of MoonBEAM including the expected effective area, localization ability and duty cycle. MoonBEAM provides many advantages to the gamma-ray and gravitational-wave follow up community through the reduction of the region needed to searched to identify the afterglow and kilanova emission. In addition, the all-sky coverage will provide insight into the conditions that lead to a successful relativistic jet, instead of a shock breakout event, or a completely failed jet in the case of core collapse supernovae.