It’s not that the battery power is the deal breaker for that, the groups are actually “functional groups”. Outdoor wco s and plugged in cameras function as cameras, whereas the doorbell cameras function as doorbells. Cameras and doorbells function differently, so the grouping of the different functional devices would need to decided and implemented. It’s not as drastic and noticable as grouping cameras and bulbs, but those are two seperate functional devices and don’t group either with the same fundamental issue.
There is also a existing wish list for grouping different functional device types, which would also cover grouping cameras and doorbells.