I think an important functionality would be able to search with a prefixed exclamation mark to be able to specify an unfederated community, such as !community@lemmyinstance.com
Im still learning the ropes here but I think that’s an important thing to be able to do from wefwef?
It also prevents your e-mail client from starting up, as your OS will probably consider the community address an e-mail address if it doesn’t start with an exclamation mark.