What are phones good for?
Not being obese!
Even though the current generation have some strange addiction to their devices and have an issue with obesity, some applications that you can install on your smart phones can help you keep track of fitness programs or diets. Apps like Calorie Counter (original name #1) counts the calories you consume each day with every processed greasy meal you pigs consume, and then tells you if you are healthy or not (which you aren't). Although you probably care more about the recent cat video that just went viral on YouTube.
What about health problems?
Yup, they do health problems too.
I'm pretty sure there is even one that tells you when it is the optimal time to commit euthanasia on a loved one in a coma via calculating the chances of them waking up. But that is too morbid for the general public and probably was taken down.
Anyway, some apps help you with monitoring things like your sugar levels if you have diabetes. Obviously that's only if you have type 1 diabetes, because if you had type 2 you would be a bit more worried.