I've forwarded notification emails several times, either because it was the quickest way to point a friend to a comment they might otherwise not have seen, or because I wanted to reply privately via email instead of publicly - it gives more context than trying to PM based on a comment.

As I understand it, the new method is slightly less secure than it is currently, as they would only need to spoof my email address instead of my login cookie, but I can reset it if I'm really worried, and I only really forward stuff to friends anyway.