you seem knowledgeable, is there a way to do this with every possible email address at your domain? Forward them all to that single other box?
And, if your mail client’s UI allows, you can even send from <whatever>@yourdoma.in to avoid disclosing your “real” address when you reply.
My favorite use-case: you sign up for foo.com with foo@yourdomain.com. Then foo sells their contact database, and now you’re getting viagra spam all day. Ok, just add a filter to auto-trash anything addressed to foo@, and the problem is solved.