This is very cool because it allows you to use any model. Obviously, it still lets the model and its operator see the entire context of the conversation.

I quite like Moxie's Confer[1] approach to just encrypt the whole thing in such a way that no one except the end-user sees the plaintext.

[1] https://confer.to/

That looks interesting. I would like to see them update the Privacy Policy and Terms to acknowledge that their service also works with an Apple ID or with another email. At present, it suggests that the only authentication allowed on your end is through Google's GMail.