"Once the attacker has root on your Glass, they have much more power than if they had access to your phone or even your computer: they have control over a camera and a microphone that are attached to your head. A bugged Glass doesn't just watch your every move: it watches everything you are looking at (intentionally or furtively) and hears everything you do. The only thing it doesn't know are your thoughts.
The obvious problem, of course, is that you might be using it in fairly private situations. Yesterday, Robert Scoble demonstrated on his Google+ feed that it survived being in the shower with him. Thankfully (for him, and possibly for us), this extreme dedication to around-the-clock usage of Glass also protects him from malicious attacks: good luck getting even a minute alone with his hardware ;P.
However, a more subtle issue is that, in a way, it also hacks into every device you interact with. It knows all your passwords, for example, as it can watch you type them. It even manages to monitor your usage of otherwise safe, old-fashioned technology: it watches you enter door codes, it takes pictures of your keys, and it records what you write using a pen and paper. Nothing is safe once your Glass has been hacked.
