Until this thread, I thought Spiked Buckler was basically a [mwcard=MW1Q04]Deflection Bracers[/mwcard] with built-in counterstrike that only performed an attack when the defense was successful. I hadn't really considered using it as a primary attack, and didn't consider that it's attack, whether used as an action or as a counterstrike, stacked with other melee buffs.
I guess for most mages, as a melee attack action, the only benefit of using the Buckler's attack over the basic 3-dice melee attack is Piercing +1, but it could be especially beneficial for mages lacking a natural 3-dice primary attack (like Adramelech Warlock and Priest of Malakai). And unlike [mwcard=FWQ01]Dancing Scimitar[/mwcard], it stacks with Battle Skill and any other melee buffs on your mage, even when counterstriking... That can be huge!
So I guess a better way to think about Spiked Buckler might be that it's a melee weapon (3-dice attack with Piercing +1) that uniquely provides an attack with the Counterstrike trait (limited to once per round on a d12>7), and that also happens to double as Deflection Bracers.