I'm a type 1 diabetic. There is a device by Dexcom known as a continuous glucose monitor that reads my blood sugar via interstitial fluids and then transmits the information via Bluetooth.
When I get unexplained low blood sugars in my sleep, which is believed to be the cause of Dead in Bed Syndrome, it sounds an alarm on the iPhone to wake me up before it's too late.
As for going with the iPhone 6
1) my money would still have gone to Apple
2) I didn't think about what a pain it was until after I bought them
Side notes
1) I have contacted Dexcom regarding an app for Android, but it doesn't seem like it will happen anytime soon.
2) I also tried an open source version for Android, but after purchasing 4 phones in a row that it had varying problems with I decided my life was worth more than being able to stay on Android.
[EDIT]
Diabetes is the number 7 leading cause of death in the United States and low blood sugar is the number one reason for ER visits by Type 1 diabetics.