Try it. Log in with #[4] public key (nPub). Then you will see what you can and can not see.
Discussion
I can't login to Ed's account though. I can see EDs public posts because I know his username (nPub). I for sure can't see his DMs....
I guess what you are saying is we can't hide our comments if someone knows our public key...and that is for sure different than other platforms. So good point on being mindful about who you share with if you want to stay Annon.
You can log in with his nPub. You would have to log out of your own account first or try another (web) client.
Here is an example of what everybody can see of your own DMs when logging in with your nPub.
We can see who you sent messages to and when. Jeff in this example. We can just not the content which is encrypted with your secret key.
Indeed. Wow. Thanks for helping to grok this better. I stand corrected.