Another angle is the processing cost, I assume Google is seeking to offload the computation for whatever features this covers from their own data centers to end users. On the scale of billions that's probably measurable and from google's side worth doing whether the users is paying for the service or not, and each of them will have more power usage with some reduced battery life on portable devices. At that scale I'd also wonder about efficiency based on what proportion of end users are using AI or running it on CPU/GPU/NPU.