...my reply got blocked by my own filter...

Random example. Say I block "🥑" -- I'd want that to apply to notes or usernames / display names. If I don't want to see a note about 🥑 I want to see notes from an account dedicated to 🥑 even less. Blocking each npub individually works, but this would be even more efficient.  

 I think I understand. People often use a particular term or emoji in their displayname to associate themselves with a particular cause/group/activity. You'd like to be able to mute the term or emoji to not only to avoid notes that contain it, but also to mute npubs that include it in their displayname.  

 Yes. Prime example would be the 18 with line through it for NSFW content.