there's no difference in terms of spam prevention, its really just to have an anchor for the creator to define the name, banner, and description. if you don't care about those things you can just use a hashtag (#physics) or namespace (!sci.physics.quantum) anchor.

I've always wanted explicit to/cc on notes, so I would throw that in there as well for relay filtering and better hinting:

https://github.com/damus-io/notedeck/issues/788#issuecomment-2734024701