Recently Pi coin got listed and it got average response from buyers. Do you see lot of potential in projects like these because mobiles are very common these days ?
personally I don't believe these mobile mining project to be mining anything, I think it's just artificial mining activity.
if you truly mining something maybe solving puzzle your mobile phone will be the one that's gonna have shorter lifespan, considering the nature of mobile phone where there's no active cooling I'd expect the repair cost would outweigh the profit generated.
also in the case of Pi, i don't really think it's mining anything. though I never really try to learn about. the mechanism of pi.