Like many people, a smartphone is an essential device in the course of my work. However, for persons who are perhaps retired those phones can still be essential to their safety in the course of their lives.
By example, when I get into my car my phone automatically links into the vehicles computer system. Should there be a vehicle accident which resulted in me being totally incapacitated the car computer system recognises there has been an incident, automatically informs the phone which then rings the emergency services.
The phone will then autonomously inform the emergency services who I am, the vehicle registration number, and exactly where the accident has taken place.
There are many other such similar applications which can be set up in cases of sudden illness etc.
So, in my view, it is well worth carrying a smartphone if only for such occurrences as the above.