Yes, but it's a matter of what I receive, not what I send. I can't control when others send me things, and I don't want to wake up one morning and find a 5 MB attachment in my inbox, and realize that I cannot access any other messages I received that morning.
Plus, email can be easy, even if it isn't efficent.
But just out of curiousity, what are the efficient file transferring ways you are thinking of? Sometimes posting things online, or direct connecting on AIM, or any of those methods, can be tedious.
\"Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.\" -Archimedes