Are you unhappy that your phone beeps every time you receive an SMS? Why should email be treated differently? The problem being that if you are out of hearing range when the first email arrives, you never know you've got a stack of new emails waiting to be read until you pick up your phone and look at the lock screen, as it doesn't alert you to the arrival of subsequent emails. I'd be happy for it to be an option, though I really don't see why the current behaviour is the default, no other mobile device behaves like this, only N9 and Jolla. I class it as a bug as it's nonsensical behaviour if you depend on email notifications.