Yes, there are a very good convenience.

In what way(s) do they make life easier?

They are good in an emergency. They are good when you are out of town. They are good when you are late at night.

When do you get frustrated when you see people on their cell phones (i.e. in the grocery store, in cars, etc.)?

I don't get frustrated when I see people on their cell phones.

Why does this frustrate you?

It doesn't. When you need to make a phone call, you need to make a phone call.