Need? Food is a need. A component group is not. That said, Athena is 11s, while Centaur is 10s. Offering a lower cost 11s group is good for Campy. It's likely a move to bridge the transition from 10s to 11s for customers, and that Centaur--or one of the lower groups--might disappear next year or the year after.
This could also help get Campy 11s spec'd on more bikes in the future, but Campy has never really been interested in OEM bike sales.
Personally, I don't see a need for Shimano or SRAM, but they appear to be doing business anyway. If Athena sells, then bringing out a new Athena flavor was a good move on Campy's part. Personally, I think the Athena group looks pretty sharp.