"You and I 'get' them but will a person who is currently 70+?"

Great point. To my mind this is the biggest issue so let's take it apart by asking ourselves why we get them?

I think it's because WE benefit from the flexibility, reachability, ease of use, low cost, convenience, pervasiveness, always on, always accessible, inbuilt payment mechanism, permanency, availability at the point of creative inspiration, etc. etc.

Why shouldn't smart phones be able to deliver this to seniors?

From what I can see it isn't because the technology isn't ready it's because the services aren't there yet...

It is obvious that the services will be different and that it will take a stretch of the imagination of the best young designers but a wrist worn smartphone will be worn (despite the discomfort) by seniors when it can predict and alert the user to:
• the fact that they are about to fall
• the fact that they are about to have a heart attack unless they do A B and C
• the fact that they are in an environment made up of dangerous levels of CO, smoke etc.
• the need to take another medication in order to follow their highly personalised medication treatment
• crime and other risks to their personal safety