OTS systems are very useful for when two people are speaking to each other and need their lines. It can be two actors having a dialogue, or a host interviewing an expert.. each seeing their respective questions or answers. These are also useful for when a spokesperson has to “look around the audience” and have multiple monitors scattered around as a resource.
Pro tip: never have the talent actually look at each other— only the monitors— so there’s no eye wandering to give the effect away.
You can use a single monitor next to the camera to simulate an interviewer, too. This makes it look “documentary style,” adds some credibility to the format, and allows the talent to give the perfect answer.