"On-device AI means less data centre costs."

From my perspective, not wasting a ton of energy at the data center is a huge win.

And it means you saved battery life by not firing up the radios to make/receive the requests. And achieved better security and privacy. And obtained faster responses. And it means you can use it for more background tasks that, again, don't waste energy making background requests to a server.

All of those things are better for the user, and just once I wish people would consider that over mysterious nefarious conspiracy theories.