See, I used to do that before I switched to iCloud completely. I have two accounts for iTunes and iCloud still even. And even if someone would hack into my "supposed" e-mail account, surprise! No e-mail in sight.
Lots of people have gotten their e-mail accounts hacked into. And every time, the idiots try and attack more accounts by doing a simple send to all in contacts blast.
Where do you usually check e-mail? On your phone, or on your computer. Rarely do most of us do this on gadgets that our not ours, and if you do, well think about the fact that anyone can get into your Facebook and bank account pretty easily with that login information.
A contact list these days is just much better to have in your phone, and with all the hacks happening now, even better to have it away from your main inbox. You can pull them up on the iCloud website anyway.