Di2 is also commonly used in consumer grade electric cargo bicycles, used by a lot of people every day to take their kids to school and back. You don't want your gears to fail while doing that.

I would imagine the sporting body would be concerned that any crowd member with a flipper zero could remotely shift gears on a racer's bike and possibly render it immobile.

These have been in flagship consumer models for years now, and gradually drifting down into more mid-high level road bikes. Still talking about the $2k+ range but totally normal in the kind of bike your dentist or, frankly on HN, your coworkers, ride.