Maybe I'm biased because I've done some intelligent agent work when I was back at Microsoft, but I really like how Allo handled this. They let the user decide whether or not they want convenience, or strict privacy. This is how it should be - up to the user.

Some people want the convenience of having their messages be stored in the cloud and helper bots to add relevant content to the mix, some people want a reduced experience but with the reward of privacy.