There are simple and compelling reasons penned by the creator[0]. I ain't an expert in security, although the key idea of a local backend with P2P activities makes intuitive sense to secure data from eavesdropping.
Ideas from a related project[1] like de-centralization, self-management of small servers (as opposed to server farms) distributed around the globe could be leveraged in cryptosphere? Diagram explaining interactions in Elijah[2]
[0] http://tonyarcieri.com/the-cloud-isnt-dead-it-just-needs-to-...
[2] https://github.com/cmusatyalab/elijah-cloudlet/blob/master/d...