In the final analysis, it is always about the almighty dollar. Clearly companies are branding themselves as a marketing strategy in attempts to distinguish themselves in an otherwise commoditized field.
Some brands will offer the consumer added value. The vast majority will fall terribly short of that threshold. The same is true about toothpaste, tampons, and tonic water, among other things
Lori, the branded diamonds are intended to offer "perceived value" to the buyer, not actual value. In advertising the term to "add value" means only in the mind of the consumer, not in reality. If you read the NY Times article further up on this thread, it clearly explains that branding is meant to "increase margins" for the sellers, "not to benefit the consumer".
Diamonds are a commodity as the article states; "like coal and corn" and I suspect that the experiments with the branding of diamonds will fail.
By the way, one of the diamond dealers who regularly contributes to this forum revealed that often, a cutter will sell the same exact stone with or without the brand. Placing brands on diamonds is an attempt to get you to pay more for something you can get unbranded, at a lower price.