It might be helpful here to categorize the data as sensitive, personal, financial, chat, public comments as such and then apply the probability model on a given category. I would probably call the AI coding as misnomer too, what you have is a higher level of auto complete functions and natural language processing.

Theoretically even I love the idea of independence, however practicality of such a thing has to be evaluated. From all the examples that exists as of today, a true and meaningful decentralization is not viable in the absence of a a trusted centralized component.