I completely agree with the examples you cite. However the parent was giving examples about auto-correction for user's contacts. That is user-specific data and there's no need for it to be shared with a third-party.
Ah, I understand. I interpreted that comment as a list of 3 separate examples where centralization helps.
A nitpick:
Auto-correction for a user's contacts could probably be done on-device, although I'd guess that machine learning across all users will probably massively reduce your success rate. Consider an ambiguous correction; you accidentally type "Gob", but have contacts of "Rob" and "Bob". I imagine that ranking the suggestions can be improved using a globally trained model.
A nitpick:
Auto-correction for a user's contacts could probably be done on-device, although I'd guess that machine learning across all users will probably massively reduce your success rate. Consider an ambiguous correction; you accidentally type "Gob", but have contacts of "Rob" and "Bob". I imagine that ranking the suggestions can be improved using a globally trained model.