Just because a certain requests don’t work offline, that doesn’t mean that Google isn’t actually running models locally for many requests.

My pixel isn’t new enough to run nano. What are some examples of offline processing not working?

I wouldn’t be surprised if the handshake between Pro and Nano was intermingled for certain requests. Some stuff done in the cloud, and some stuff done locally for speed - but if the internet is off, they kill the processing of the request entirely because half of the required platform isn’t available.