I'm also missing this feature. It would be very helpful, to have email notification options for the below cases:
- when a new bug is added: this is useful for the developer or support team to be notified when a new bug is reported, to take action (I'd set this as unchecked by default)
- when a bug is assigned to someone: the assigned person should be notified to take action (I'd set this as checked by default)
Hope you will implement this minor feature soon. I consider it a very useful one, which will improve the user experience. 
Thanks