privacy

If you really mean that, the leak resulting from such a mistake will only happen if you missed the fact that your chat history is saved after a talk (even though it's right there just like any other history), then enough time passed for your friend to change views on you and leak whatever they had saved (since you didn't remove that part of chat history before that happened).

I'm sure that such a scenario is insanely unlikely. A much more likely scenario would be for you to not know that a friend of yours already changed their views and making records of all end to end encrypted content you make together by simple means, like another phone.

I like when people hate questionable stuff. But I hate when they do it for silly or made up reasons.