Besides what other have answered you already have a lot of wireless connections on a race bike. To the sensors measuring speed, cadence, watts, and possibly stuff like rear traffic radar, gear selection etc..
It all integrates with an unwired bike computer, so wireless shifters makes fine sense in the system.
Well speed is something a large portion of cyclists have always wanted. Adding a cycle computer or even a mechanical speedometer in earlier times was always popular. Now GPS units and smartphone mounts, or just logging your ride in an app using your phone or smartwatch are popular.
Cadence and pedal force are very useful for training and competition (organised or the self-improvement kind), so pretty much for the same cyclists that would also want wireless shifting.
We can do that. (I barely “measure” in the sense that I’m lazy and just pedal slowly, haha).
But there’s a well established community of really hardcore bicycle hobbyists. The folks paying a couple thousand dollars for shifters want fancy stuff. Some want graphs and numbers. shrug
It all integrates with an unwired bike computer, so wireless shifters makes fine sense in the system.