A piece of ice that can't be bypassed? Looks great on paper right? The problem with Guard is that the most common source of bypassing ice (Femme Fatale) can just break this anyway. If it had been strength 4 or a barrier, for example, then I think it would justify it's 4c rez cost. As it is, there are too many other good options to justify a card whose only purpose is to block an Inside Job.
(I will make one final remark in this cards favour however - Inazuma Guard I have found to quite an effective early game scoring server.)