It's meant to interfere with your writing, like a backseat driver interferes with your driving. Your idea of separation is interesting, do you see it as a kind of translator?

I imagine a backseat driver shouts suggestions, but does not take over the wheel; like the way autocomplete is there without preventing you from typing something else. It doesn't have to be a translator, but there should be some distinction between user input and what comes from the model, and the user should have the final say.