Wouldn't REAL-ID = Security Risk?

I'm just curious if giving out our blizz.net account e-mail to add friends is a good idea.
I understand that blizzard wants us to use this for our IRL friends mostly, but that is very limiting.

What if I want one of my guild members to be able to contact me?
Or to be-friend an awesome pug from LFG / BGs?
There are many instances where I wouldn't mind someone being able to contact me but I wouldn't want them having the e-mail I use for my entire account.

I think it be safer to allow us to choose a unique ID for our entire blizz.net account instead of having our e-mail be our ID, fore many reasons, but especially when Real-ID goes live.