Since I’m using my watch for sleep tracking, I think it doesn’t make sense to consume the phone battery when it just lays on the counter. I never leave my phone charging for a night to protect the battery.
Therefore, I think the WearOS app could actually record all the sensors and just sync it with the phone app after waking up. The phone could be potentially woken up slightly before the alarm, so the smart alarm will still work.
The current behavior, when the WearOS app just opens the application on the smartphone unnecessary consumes the phone battery when the phone does nothing.