Yes Dcmd99 speed/perfomance is required.
Interconnect are the bottleneck of the datacenters.
Don't forget the small from factor as it may prove to be another incentive as well.
Please, for general knowledge, there is a powerpoint presentation regarding direct attach copper calbe at this link:
https://www.bicsi.org/uploadedFiles/BICSI_Website/Global_Community/Presentations_and_Photos/Southeast_Asia/2012_SEA/2.6%20ABC%20of%20Direct%20Attached%20Cables.pdf