While it may mean a less complex pilot to aircraft interface, as long as that app is not able to interpret the weather, avoid other aircraft and obstacles, do the RT, deal with strange requests from ATC, sort out the emergencies, carry out the inflight decision making and overall, act like a responsible human being, I don't see it catching on anytime soon.
The sad thing is that IT technology is getting closer and closer to being able to deal with all the stuff I just listed....