It is a good idea in theory, but what if you no longer have access to the email? Like lavabit shutting down, you cannot access the email to confirm that you want to change your email. 
You deal with the admin, I don't think it's something that will happen very often.
I lost one email address once because their whole database got compromised and they decided, for the sake of their users (...), to reset all passwords and the only way they cared to send a new password was to "the secondary email" which I did not have defined. They seemed like a perfectly fine service until that very occasion.
