After the direct hit of Naruto's rasengan he manages to break Tobi's mask but at the same time squashing his face, therefore causing an unclarified identity of the mushed face. We will never know who was the man behind the mask.
It's not pointless. COME ON. A rasengan to the face? It broke the mask, how much more can it damage the face? Imagine someone hitting your face with a golf club at full speed.
But sadly, knowing the flow of the story, it wont be too much damage because he still needs to speak and show his face with dramatic music accompanying the revelation.