Since they make it out for health, why not a simple blood alcohol test? Diabetic blood sugar test would also be helpful for many. These could be little add on options. Also, make it contain a quick lookup for your medical parameters like blood type, chronic conditions, next of kin to call in an emergency. For aging adults a feature of " I have fallen and cant get up" with a gps location. Lots of stuff to be added. An insect repellant (sends out sound waves which insects do not like) would be nice when walking in the woods. Also, when in NYC it would be nice to have a needle with a potent chemical that would freeze a mugger attempting to rob you. Then I would pay 500 bucks for it.
Also, if it could talk to my car and garage door opener (learn the codes like my car does) so I don't have to mess with keys. (it has a microphone so it would recognize my voice and open when I say "open the damn garage door ") .
A quick button that would ring my cellphone to get me out of a meeting or boring conversation would be nice also. (without offending the parties involved.)