I think with choice being available this sort of thing could be useful in some circumstances to some people.
But many problems need a hands on approach by a doc to get to the bottom of the problem. And also some people will be unable to get to grips with an app based solution or might not have a capable phone. Many of those patient will be the docs most regular visitors, i.e. the elderly.
The cynic in me thinks choice won't be there and we'll all have to be screened by the robo doc before we're worthy of making an appointment. Also it'd make charging for missed appointments nice and easy wouldn't it?