Chimp vs human! - Working Memory test

"Ayumu the chimpanzee has made headlines around the world for his ability to beat humans on memory tests, in both speed and accuracy. Does Ayumu's ability force us to reconsider our assumptions about human superiority to other primates?"

I've seen these experiments before. There are even apps where you can attempt to beat the scores and times of Chimpanzees (such as 'Ape Test'). Their cognitive abilities, i.e. 'intelligence', are clearly superior to homo sapiens in this particular area. But why? How does this ability benefit them in their natural habitat? I've yet to read of a convincing answer. As our favorite Vulcan would say, "Fascinating".