If they can optimized that app to work with lesser battery consumption and not affecting much the functional apps necessarily needed in android phones like messenger and cameras then I think it would be a really good project. Android phones were known to being used via multitasking since it is made that way but we all know that mining needs a lot of computing power in which the phones itself do not have much compared to the usual miners so I think one of the challenges of these project is optimization of that program to work seamlessly on phones which are already saturated with apps.