Agreed that monitoring the battery life of the IEM pack would be the top use case and that has its challenges. However, transmitter monitoring is also helpful in cases where the engineer is mixing monitors from FOH. That way, the engineer can monitor the transmitter to be able to confirm audio is being sent to the receiver, and confirm the transmitter is not clipping. To make this happen, the transmitters have to be at FOH with the engineer, or even better would be networked, placed at side stage and remotely monitored, which would often be preferred from an RF standpoint