Just what people need; a false sense of security…

You don’t need an export button to save copies of a chat. Even if screenshots are blocked and you’re not running an OS that lets you bypass that, you can always take photos/video of the screen when all else fails.

Once you’ve sent data, it is no longer in your control. Messages, emails, posts, files, replies, encrypted end-to-end chat applications, all of it: Don’t send it if you don’t want someone somewhere to keep a copy. Maybe they did, maybe they didn’t; it’s no longer in your control once it has left your device.