Hello!
I dont know how useful this is as a stock photograph so I will leave that comment to others and just focus on the image and how it was presented. I actually like your very shallow depth of field. It might be the strongest part of this picture. Your composition is good although I think the box needed to be closed or the top included. The top part of the box is bothersome as my eye keeps wondering up there away from the cubes. I think I would have rather preferred the background to be darker than the foreground under the the box and cubes. I think that would have kept my attention more down in front. Overall, I think you did a good job.
Well it's a shame most people didn't get the humour of entering an image of stock cubes into a stock photography challenge but I think it's very funny. And I also think it's a well-composed and balanced image with good use of slightly shallow DOF and of colour.
It's almost as if you are trying to do the "enitire" ad....whereas you should be trying for a picture of just a "subject" that a marketer could use in composing an ad.