It has more benefits than knowing who leaked your email, it lets you easily filter your incoming email by who you gave the email to, and when your email is leaked it lets you shut off that email address. Of course you can also filter your email by the sender's domain, but that isn't as consistent, and doesn't help at all when your email address has been leaked.
It's true that you do have to set it up so that you can send email from the addresses to avoid not being able to reply by email, and you will want a password-manager or something to remember exactly what email you used, for convenience.
Personally I'm glad I've done this, it's made it much easier to organize my emails.