One of the neatest uses I've seen was a workman working up on the roof keeping in touch with his mate on the ground, without having to bellow.

Or if I'm out in the shed I'm still reachable. And if I've lost my key coming in I can phone and say "let me in".

It's just not the same way of using it as the way I use a traditional phone. It's the same kind of difference as between when it was a matter of there being a phone box on the corner, and when we had a phone installed in the house.