Can you revoke your nsec if it has been compromised? To alert your contacts of such issue.
Can you encrypt a message to several users at once instead of sending a copy to every one? In the last case how would a group of users know the recieved the exact same message.
Can I clear sign a message in nostr with revokable nsec?
These are some uses I missed, but maybe NOSTR does it and I'm just unaware.