You're missing the point of the video. The point is the photo mode presents the glitch where the frame rate becomes unlocked, not that photo mode in itself is important. As settings and resolution are identical as confirmed by the developers themselves then it gives a GPU benchmark, one that proves the theoretical performance advantage that Xbox has on paper.
This is enlightening not just because of this result but the absolutely pathetic straw clutching and desperation of those trying to deny what is staring them in the face, even questioning not only Digital Foundry but the developers themselves as if they are lying
I'm not talking about you in particular as you seem a reasonable person but it proves that some people are so one eyed that even with undisputable proof they still can't accept facts.
Truly tragic.