You still have to take the action to enable the AI features even if you just have a " " character in that field, no? It doesn't send anything to openAI until you open the prompt for it to do so.
If you leave the field empty (open to accident) and you don't press this button in this function that you may use for other things (open to accident) it doesn't send data where you didn't expect it to. This is functionally equivalent to you can accidentally send data you didn't mean to. This is simply prevented with a real toggle to disable the function.
I don't know about you, but I have clicked on things I didn't mean to because I lost where the mouse is, or because I'm giving a window focus again, it is not an accident that doesn't happen.