Over time, people will come to rely more on their phone to keep them healthy than they do on their actual doctor. Rather than going once a year for a check-up and to get a few basic tests done, you will be monitored day in and day out by your phone. This does not mean that doctors will go away, but it does mean that the role of the doctor will be forever altered. It also means that doctors will be empowered with a lot more data on what their patients are up to between visits, which will help them provide better care.
I don't for a minute think that I'm going to be able to replace my doctor (or think that you should replace yours!) but I do firmly believe that these devices will allow us to do more and better tracking of relevant therapy information allow for much more efficient use of therapy time and measures of progress. This, I'm my opinion, is a good thing.