If you use autopilot to assist you flying the model, a delay is not a big problem. However, most people fly models in full manual, with the FPV setup giving the

If you use autopilot to assist you flying the model, a delay is not a big problem. However, most people fly models in full manual, with the FPV setup giving them an "in-cockpit" experience. Even for fairly slow multicopters, a latency of >100ms is really bad for anything except slow hovering over open terrain (which gets incredibly boring very quickly).