This concept certainly sounds appealing simply because of the sheer number of smartphones out there...2.2BLN! My concern, though, revolves more around the security aspect of this mobile-centric mining platform. Considering how much unfettered data access we give to so many apps on our phones, smartphones, unlike PCs, are inherently insecure. Will this leave our most important devices vulnerable to hacks?
They're implementing 2FA security to both phones and PC once the ICO is over. If you're worried about people hacking your phone because of an app, than I really don't know how to respond. I don't know the frequency or have heard of anyone hacking a smartphone for nefarious reasons, but I could be wrong.